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Nutrient File Technique
3Mar

Hydroponic System: NFT – Nutrient Film Technique System

By | March 3, 2017

N.F.T. (Nutrient Film Technique) System

 

The N.F.T. system  (Nutrient Film Technique) is quite popular with home hydroponic growers as well. Mainly because of it’s fairly simple design. However N.F.T. systems are best suited for, and most commonly used for growing smaller quick growing plants like different types of lettuce. Along with growing lettuce, some commercial growers also grow different types of herbs and baby greens using N.F.T. systems.

While there are a lot of different ways design an N.F.T. system, they all have the same characteristic of a very shallow nutrient solution cascading downward through the  tubing. Where the bare roots of the plants come in contact with the water, and can absorb the nutrients from it. The major downside to an N.F.T. systems is that the plants are very sensitive to interruptions in the flow of water from power outages (or whatever reason). The plants will begin to wilt very quickly any time the water stops flowing through the system.

 What you need to build a N.F.T. system:
  • Container to hold the nutrient solution (a reservoir)
  • Submersible fountain/pond pump
  • Tubing to distribute water from the pump to the N.F.T. growing tubes
  • Growing tubes for the plants to grow in (also called a gully/channel)
  • starter cubes, or small baskets and growing media to start seedlings in
  • Return system (tubing, channels) to guide the used nutrient solution back to the reservoir

How a hydroponic  N.F.T. system  operates is fairly simple. Nutrient solution is pumped up from the reservoir, usually to a manifold that connects the larger tubing to a number of smaller ones. Each one of these smaller tubes runs nutrient solution to one side of each one of the growing channels/gully’s with the plants in it. A thin layer (film) of the nutrient solution flows through each of the channel’s with the plants in it to the other side, passing by each plant and wetting the roots on the bottom of the channel as it does. The nutrient solution flows from one side to the other because the channel is sloped slightly so the water flows down hill.

The plants in the growing tubes (channel/gully) are typically suspended above the water by placing seedlings started in starter cubes or small one inch baskets of growing media into small holes in the top of the tube. The roots of the seedlings hang down to the bottom of the tube/channel where they get nutrients from the shallow film of nutrient solution flowing by. The excess nutrient solution flowing out of the low end of each of the channels drains into another channel or tube, and guided back to the reservoir where it is recirculated through the system again.

While the nutrient solution flowing through the channels is very shallow, the entire plants root mass remains moist from the roots being able to wick up moisture on the outside of the roots, as well as through humidity that’s kept within the tube/channel. The roots that are suspended between the base of the plant and the water level in the channel not only have moisture to access, but are also able to get plenty oxygen from the air surrounding them within the tube/channel as well.

Commercial growers typically use specially made channels/gully’s for N.F.T. systems that have flat bottoms with grooves running lengthwise along the channel. These grooves allow water to flow underneath the root mass and help keep it from pooling or damming up. Home growers often use vinyl rain gutter down spouts for their channels. These vinyl down spouts have similar grooves, but cost just a fraction of what the commercially made channels/gully’s cost. Home growers also often use round ADS (Advanced Drainage System) irrigation tubing for N.F.T. systems. The ADS tubing doesn’t have grooves, but with increasing the slope to compensate, the round tubing works well also.

N.F.T. system Flow rate, and channel slope
How deep should the water be, and how fast should the water be flowing are the two most common questions asked about this type of system. First the slope of the channel controls how fast the water goes through the tube/channel (not the water pump or).

The recommended slope for a N.F.T. system is typically a 1:30 to 1:40 ratio. That is for every 30 to 40 inches of horizontal length, one inch of drop (slope) is recommended. We recommend when designing your N.F.T. systems, you design it so you can adjust the slope while the plants are still growing. That’s because as the root systems get bigger, they may cause it to pool and dam up the water flow. If it’s adjustable you can tilt it more to compensate if needed.  Also when building your N.F.T. systems, try and keep the channels/gully’s as true as possible. If they sag in spots, water will pool up in those areas.

The recommended flow rate for a N.F.T. system is typically between 1/4 gallon to 1/2 gallon per minute (1 to 2 liter’s) for each grow tube (channel/gully). Or between 15 gallons to 30 gallons per hour (60 to 120 liter’s). While the plants are just seedlings the recommended flow rate can be cut in half, and then increased as the plants get bigger. Flow rates much higher or lower than these have sometimes been associated with nutrient deficiencies. Also nutrient deficiencies have sometimes been seen when growing tubes (channel/gully) are longer than 30 to 40 feet (10 to 15 meters). However it’s been shown that having a second nutrient feed line half way down the growing tube (channel/gully) eliminates that issue.

 

EBB and Flow System
3Mar

Hydroponic System: EBB & Flow

By | March 3, 2017

Ebb & Flow – (Flood and Drain) System

 

Flood and Drain (Ebb and Flow) systems are very popular with home hydroponic growers for many reasons. Besides how easy they are for anyone to build, you can use almost any materials you have laying around to build them with, so you don’t need to spend much money to grow plants  hydroponically. Also they can be built to fit in any available space you might have (both indoors or outdoors), and there is no limit to the different and imaginative ways to design them for that space. Along with being inexpensive and easy to build, plants grow very well in flood and drain systems. The flood and drain system works basically like it sounds, by simply flooding the plants root system with nutrient solution. Only periodically rather than continuously.

How a hydroponic flood and drain system operates quite simple. The main part of the flood and drain system holds the containers the plants are growing in. It can be just one plant, or many plants/containers in series. A timer turns on the pump, and water (nutrient solution) is pumped through tubing from the reservoir up into the main part of the system using a submersible fountain/pond pump. The nutrient solution continues to fill (flood) the system until it reaches the height of the preset overflow tube so that it soaks the plants roots. The overflow tube should be set to about 2 inches below the top of the growing media.

When the water filling/flooding the system reaches the overflow tube height, it drains back down to the reservoir where it recirculates back through the system again. The overflow tube sets the water level height in the flood and drain system, as well as makes sure the water (nutrient solution) doesn’t spill out the top of the system while the pump is on. When the pump shuts off, the water siphons back down into the reservoir through the pump (draining the system).

What you need to build a Flood and Drain (Ebb and Flow) system:
  • A container for the plant’s roots to grow in.
  • A container (reservoir) to hold the nutrient solution.
  • A submersible fountain/pond pump.
  • A light timer to turn the pump on and off.
  • Some tubing to run from the pump in the reservoir to the system to be flooded.
  • An overflow tube set to the height you want the water level.
  • Growing medium of some kind.

There are many different ways to build a flood and drain system, and they are very good for growing small to medium size plants. Even for growing large plants with larger flood and drain system designs. You can use just about anything to build one including buckets, tubes, 2 liter bottles, storage totes, water bottles, an old ice chest, trash cans etc.. Just about anything that can hold water can be used. The imagination doesn’t stop there either, there are many ways to flood and drain the roots in the system too. Below are some examples of how the three most common ways used to flood and drain the systems work.

(Tip 1) Make sure there is a way air can get in the top of the overflow without spilling water out. A “T” connector with an extension that is a few inches above the water line will work nicely. This will keep air pockets from forming in the system and make sure it floods and drains properly.

(Tip 2) Make sure the overflow tube is bigger than the water inlet tube from the pump. Otherwise because the water is only going out through gravity, and water is coming in through pressure from the pump, you could wind up pumping in more water than what is going out the overflow. That would lead to water building up and spilling out the top of your system, unless you reduce the pressure (volume) from the pump.

There are basically three main types of flood and drain system setups

Plant containers in series design
This type of setup is most commonly used when many different containers with plants are being watered (flooded) at the same time. It’s important to remember that the system with the plants (containers) to be flooded (watered) needs to be above the reservoir, like on a table top or bench. That way the water can flow back to the reservoir by simple gravity, and thus drain the system correctly.

First multiple containers are all connected
together through tubing so that when the system is flooded, they all flood evenly, and all at the same time. For simplicity, instead of having a separate overflow for each container being flooded, there’s usually only one overflow tube. It connects to the system at the base where all the containers are connected to. And when the water height reaches the top of the overflow, it spills over and goes back to the reservoir to be pumped through the system again. The height of this one overflow tube will set the height of the water level in all of the connected containers with the plants in them (as long as it’s level). You can change the water height in all of the connected containers by simply adjusting the height of the single overflow tube.

Flooding tray design
The flooding table/tray flood and drain (ebb and flow) system type setup is useful when you want to place plants in the system temporarily, need to be moving them around a lot, or starting plants to be placed in another larger system. Instead of flooding separate containers with plants in it, this method only floods one container. Usually a shallow square or rectangle container that sets on top of a table. The reservoir usually sits directly underneath with easy access.

Water is pumped up from the reservoir into the flooding tray on one side, and the overflow is on the other side of the flooding tray. That makes sure the water actually circulates from one side of the tray/table to the other. Like any flood and drain (ebb and flow) system, the overflow tube height sets the water height during the flooding cycle, and can be adjusted as needed.

The plants are grown in regular plastic pots or baskets, and placed in the flooding tray like regular potted plants. However, unlike regular potted plants, hydroponic growing media is used to pot the plants instead of using potting soil. Once the plants get big enough, they can be transferred into a permanent hydroponic system.

One downside to using the flooding table is the algae growth, and should be cleaned out regularly. Because the top of the tray is usually left open, light is allowed to get in to the nutrient solution in the bottom of the tray, That allows algae to grow. The algae alone isn’t really bad for the plants, but it does use up dissolved oxygen in the water.

Serge tank flood and drain (ebb and flow) system design

The serge tank type of flood and drain setup is useful when more vertical space is needed. Typically with flood and drain systems, the reservoir is always lower than the hydropnic system. That’s so the water (nutrient solution) can drain out of the system through gravity back into the reservoir through the overflow, and when the pump is off. But you can still set up a flood and drain system even when the water level in the reservoir is higher than the hydroponic system it’s supposed to flood and drain back from. That is with the use of a serge tank.

The serge tank type of flood and drain system costs more to build because there are many more parts needed. It works on the principal that water seeks it’s own level. In other words, the water height in one container will be the same in another container when they are connected below the water line. The serge tank serves as a temporary reservoir that controls the water height in all the containers with the plants in them, and is only full during the flooding cycle.

The serge tank flood and drain (ebb and flow) system operates by pumping water (nutrient solution) from the much larger main reservoir into the serge tank when the pump timer goes on. As the water level rises in the serge tank, the water level rises evenly in all the connected plant containers at the same time. When the water level gets high enough, a float valve in the serge tank turns on a pump in the serge tank. The pump in the serge tank then pumps water back into the main reservoir. At this time both the pumps are on (pump in main reservoir, and serge tank).

After the timer for the pump in the main reservoir shuts off, the pump in the serge tank is still on. The pump in the serge tank continues pumping all the water back into the main reservoir (draining the system) until the water level gets low enough. At that point a second float valve shuts off the pump in the serge tank.

DRIP System
3Mar

Hydroponic System: Drip

By | March 3, 2017

Hydroponic Drip Systems

 

Drip systems are one of the most widely used types of hydroponic systems around the world, both for home growers as well as commercial growers alike. That’s mainly because it’s an easy concept and needs few parts, but yet it’s a very versatile and effective type of hydroponic system. Even though it’s an easy concept, it won’t limit your imagination when building your own systems. The way a drip system works is just like it sounds, you simply drip nutrient solution on the plants roots to keep them moist.

Hydroponic drip systems can easily be designed in many ways, as well as from small to large systems. But their especially useful for larger plants that take a lot of root space. That’s because you don’t need large volumes of water to flood the system, and the drip lines are easy to run over longer spaces. As well as when using a larger amount of growing media for larger plants, more growing media  retains more moisture than smaller amounts, and that’s particularly beneficial to large plants because it’s more forgiving to the plants. Forgiving meaning that the plants arent as sencitive to watering times, so they don’t stress imeditaly if they don’t get waterd on time for one reason or another.

What you’ll need to build a drip system is:
  • A container for the plant’s roots to grow in.
  • A container (reservoir) to hold the nutrient solution.
  • A submersible fountain/pond pump.
  • A light timer to turn the pump on and off.
  • Some tubing to run from the pump in the reservoir to the plants (and/or the drip lines if you use different sizes).
  • Tubing (PVC or flexible tubing) to run the return lines for the extra nutrient solution from the plants back to the to the reservoir.
  • (optional) You can use drip emitters, or you can just poke small holes in the tubing with a hot paper clip for the nutrient solution to drip out of like we like to do.
  • Growing media for the plants roots to grow in and help support the plants weight.

How a hydroponic drip system operates is simple. Water (nutrient solution) is pumped up from the reservoir through tubing to the top of the growing media (where the plants roots are), from there it drips out of the tubing onto the growing media. The nutrient solution drains down soaking both the roots and growing media all the way to the bottom of the container. From there the nutrient solution flows through an opening/s, and gravity allows the nutrient solution to flow downhill through tubing all the way back to the reservoir. It’s important to remember that the plants growing container needs to be at least 6-8 inches or so above the top of the reservoir, so that gravity can drain the excess water back do the to it (water wont flow uphill without a pump).

There are really two types of hydroponic drip systems

Recirculating/recovery drip systems
For home growers the recirculating drip systems are by far the most commonly used. The recirculating drip systems is like it sounds, it simply refers to reusing/cycling the used nutrient solution after it has wet the roots back to the reservoir where it can be recirculated through the system, and used over and over again. Recirculating systems are also called recovery systems because it refers to recovering the used nutrient solution so it can be recirculated through the system again.

Like any hydroponic system that recirculates, a recirculating drip system’s nutrient solution can change in both the pH as well as nutrient strength levels as the plants use up the nutrients in the water when it circulates over and over. Because of this, recirculating systems require that you periodically check and adjust the pH as needed, as well as change the nutrient solution regularly to maintain a balanced nutrient solution for the plants.

Non-recirculating/non-recovery drip systems
For commercial growers the non-recirculating/non-recovery drip systems are most common. While it sounds like a waist of water and nutrients not to recover and reuse it, commercial growers actually waist very little. They do this by precisely timing their watering cycles. Using special “cycle timers” they can adjust the watering times down to the minute, or even second if they need to. They water just long enough to wet the growing media. So the water (nutrient solution) they drip onto the plants is absorbed and held in the growing medium where the plants roots access it, and very little if any runs off. From time to time they flush the growing medium with plain fresh water to avoid nutrient build up in the growing medium over time.

The nutrient solution in non-recirculating/non-recovery drip systems tend to be less maintenance, mainly because of the fact that none of the used nutrient solution is recycled back into the reservoir. This means that you can fill the reservoir with a balanced, pH adjusted nutrient solution and it won’t change, so you don’t need to keep monitoring it. As long as you keep the water in the reservoir slowly moving/circulating so that the heavier mineral elements don’t settle at the bottom, it will remain a balanced pH adjusted nutrient solution.

Law by state
1Mar

Cannabis Cultivation Law: By State

By | March 1, 2017

Reference Site: https://www.leafly.com

Original Content Link: https://www.leafly.com/news/cannabis-101/home-cannabis-cultivation-laws-a-state-by-state-guide

Alaska

Possession/Use Limits: Persons 21 years of age or older may possess, use, display, purchase, and transport one (1) ounce or less of marijuana.

Grow Limits: An adult over the age of 21 may possess, grow, process, or transport no more than six (6) plants total, with no more than three (3) plants that are mature.

Resources:

Arizona

Possession/Use Limits: A qualifying patient or designated caregiver registered with ADHS may obtain and possess up to 2.5 ounces of marijuana in a 14-day period from a registered non-profit medical marijuana dispensary.

Grow Limits: A medical marijuana patient or the qualifying patient’s designated caregiver may cultivate up to twelve (12) plants if they live more than 25 miles from the nearest medical marijuana dispensary.

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California

Grow Limits: A medical marijuana patient shall not cultivate medical marijuana without obtaining a license, permit, or entitlement permitting cultivation from the city and/or county in which the cultivation will occur.

A medical marijuana patient may cultivate cannabis so long as the area they use to cultivate cannabis does not exceed 100 square feet.

This limitation does not apply to a primary caregiver cultivating marijuana if the area he or she uses to cultivate marijuana does not exceed 500 square feet and he or she cultivates marijuana exclusively for the personal medical use of no more than five (5) specified qualified patients for whom he or she is the primary caregiver and does not receive remuneration for these activities.

  • Exemption from the requirements of this section does not limit or prevent a city and/or county from regulating or banning the cultivation, storage, manufacture, transport, provision, or other activity by the exempt person, or impair the enforcement of that regulation or ban (check the laws in your local jurisdiction).

Resources:

 

Colorado

Possession/Use Limits: Colorado residents may purchase and possess up to one (1) ounce of marijuana at a time. Non-Colorado residents are limited to 1/4 ounce.

A patient’s medical use of marijuana is lawful within the following limits:

  • No more than two (2) ounces of a usable form of marijuana;
  • No more than six (6) plants, with three (3) or fewer being mature, flowering plants that producing a usable form of marijuana.

Grow Limits: Any adult resident of Colorado may grow up to six (6) plants per person, with no more than three (3) plants in the mature/flowering stage at any time. Non-Colorado residents may not cultivate cannabis.

No more than twelve (12) total plants are allowed per residence regardless of the number of adults living there. Cannabis plants must be kept in an enclosed, locked area.

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Connecticut

Possession/Use Limits: The combined amount of marijuana possessed by the qualifying patient and the primary caregiver for palliative use does not exceed an amount of usable marijuana reasonably necessary to ensure uninterrupted availability for a period of one (1) month.

Grow Limits: Home cultivation is not permitted.

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Delaware

Possession/Use Limits: Usable amount of medical marijuana for medical use is limited to six (6) ounces or less.

Grow Limits: Home cultivation is not permitted.

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District of Columbia

Possession/Use Limits: It is legal for a person who is at least 21 years old to:

  • Possess two (2) ounces or less of marijuana;
  • Transfer one (1) ounce or less of marijuana to another person who is at least 21 years old, so long as there is no payment made or any other type of exchange of goods or services;
  • Possess marijuana-related drug paraphernalia that is associated with one (1) ounce or less of marijuana;
  • Use marijuana on private property.

The maximum amount of medical marijuana any qualifying patient or caregiver may possess at any time is two (2) ounces or the equivalent of two (2) ounces of dried medical marijuana when sold in any other form.

Grow Limits: It is legal for a person who is at least 21 years old to cultivate within their residence up to six (6) marijuana plants, no more than three (3) of which are mature.

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Hawaii

Grow Limits: A registered medical marijuana program participant that indicates their intent to grow on their application may grow an “adequate supply,” or no more than seven (7) plants total and no more than 4 oz. of usable marijuana jointly between a registered patient and caregiver.

A qualifying patient may designate a caregiver on their application to grow no more than seven (7) plants total on their behalf. A caregiver may only grow for one patient at a time. Whosoever is designated to grow medical marijuana should tag each plant at the base with their 329 card number and expiration date.

Act 241 eliminates the ability of a caregiver to grow medical marijuana on behalf of a qualifying patient after December 31, 2018 (unless the patient is a minor or adult lacking legal capacity or resides on an island without a dispensary).

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Illinois

Possession/Use Limits: Adequate supply means 2.5 ounces of usable cannabis during a period of 14 days and that is derived solely from an intrastate source.

Grow Limits: Home cultivation is not permitted.

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Maine

Possession/Use Limits: A qualifying patient may possess up to 2 ½ ounces of prepared marijuana.

Grow Limits: A maximum of six (6) mature plants per patient may be cultivated for medical use. A qualifying patient who elects to cultivate marijuana plants must keep the plants in an enclosed, locked facility unless the plants are being transported because the patient is moving or taking the plants to the patient’s own property in order to cultivate them.

Minors, incapacitated adults, homeless qualifying patients, and registered patients in hospice or nursing facilities may not cultivate his or her own marijuana. Only designated primary caregivers or designated dispensaries may cultivate on behalf of the qualifying patient in this case.

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Maryland

Possession/Use Limits: Qualified medical patients may possess a sufficient 30-day supply of marijuana for medical use.

Grow Limits: Home cultivation is not permitted.

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Massachusetts

Grow Limits: A qualifying medical marijuana patient with a hardship cultivation registration may cultivate a limited number of plants sufficient to maintain a 60-day supply solely for that patient’s use. He or she may apply for a hardship cultivation registration if the patient can demonstrate that his or her access to a registered medical dispensary (RMD) is limited by:

  • Verified financial hardship
  • Physical incapacity to access reasonable transportation (an inability to use public transportation or drive oneself), lack of personal caregiver with reliable transportation, or lack of RMD that will deliver to the patient’s or personal caregiver’s primary address
  • Lack of a RMD within a reasonable distance of the patient’s residence and lack of a RMD that will deliver marijuana to the patient’s or personal caregiver’s primary address

To obtain a hardship cultivation, a registered qualifying patient shall submit:

  • A nonrefundable registration fee (unless waived due to financial hardship)
  • Information supporting a claim that access is limited to one or more of the above circumstances
  • An explanation including lack of feasible alternatives to mitigate limitations claimed
  • A description and address of the single location that shall be used for the cultivation of marijuana, which shall either be the registered qualifying patient’s or personal caregiver’s primary residence
  • A written explanation of how the qualifying patient will cultivate marijuana
  • A description of the device or system that will be used to ensure security and prevent diversion of the marijuana plants being cultivated
  • Written acknowledgement of the limitations on his or her authorization to cultivate, possess, and use marijuana for medical purposes

The Department shall review and approve or deny an application for a hardship cultivation license within 30 calendar days of receipt of a completed application.

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Michigan

Possession/Use Limits: A qualifying patient who has been issued and possesses a registry identification card shall not be subject to arrest, prosecution, or penalty in any manner, provided that the qualifying patient possesses an amount of cannabis that does not exceed 2.5 ounces of usable marijuana or twelve (12) plants kept in an enclosed, locked facility.

The privilege from arrest under this subsection applies only if the qualifying patient presents both a registry identification card and a valid driver license or government-issued identification card that bears a photographic image of the qualifying patient.

Grow Limits: A primary caregiver who has been issued and possesses a registry identification card shall not be subject to arrest, prosecution, or penalty if the primary caregiver possesses an amount of marijuana that does not exceed 2.5 ounces of usable marijuana, or twelve (12) plants kept in an enclosed, locked facility for each registered qualifying patient that has specified that the primary caregiver be allowed under state law to cultivate marijuana for the qualifying patient.

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Montana

Grow Limits: A registered cardholder may possess up to four (4) mature plants, twelve (12) seedlings, and one (1) ounce of usable marijuana.

A provider or marijuana-infused product provider may possess four (4) mature plants, twelve (12) seedlings, and one (1) ounce of usable marijuana for each registered cardholder who has named the person as the registered cardholder’s provider.

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Nevada

Possession/Use and Grow Limits: The holder of a valid registry identification card is prohibited from cultivating, growing, or producing marijuana if a dispensary opens in their county of residence. If the holder of a valid registry identification card resides in a county with no dispensaries, the holder of the card is exempt from state prosecution for:

  • Possessing, delivering, or producing no more than 2 ½ ounces of usable marijuana
  • Twelve (12) marijuana plants, irrespective of whether the plants are mature or immature

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New Hampshire

Possession/Use Limits: A qualified patient is not permitted to purchase more than two (2) ounces during a 10-day period, and is not permitted to be in possession of more than two (2) ounces of cannabis at any given time. If you have a designated caregiver, you and your designated caregiver combined cannot have more than two (2) ounces of cannabis at any given time.

Grow Limits: Home cultivation is not permitted.

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New Jersey

Possession/Use Limits: A physician shall provide written instructions for a registered qualifying patient or his caregiver to present to an Alternative Treatment Center (ATC) concerning the total amount of usable marijuana that a patient may be dispensed, in weight, in a 30-day period, which amount shall not exceed two (2) ounces. If no amount is noted, the maximum amount that may be dispensed at one time is two (2) ounces.

Grow Limits: The Compassionate Use Medical Marijuana Act does not authorize a qualifying patient or primary caregiver to grow or cultivate marijuana, or to possess a marijuana plant.

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New Mexico

Possession/Use Limits: Qualified patients are allowed to possess up to approximately eight (8) ounces (230 grams) of usable cannabis. Primary caregivers may transport up to 8 ounces for each patient listed on the caregiver ID card. (If an exception to the 8 ounce limit is granted, it is noted on the back of the patient ID card).

Grow Limits: Qualified patients may apply for a license to grow their own supply of medical cannabis. The license must be posted or kept near the growing area. A Personal Production License (PPL) allows patients to grow up to four (4) mature plants and twelve (12) seedlings at any given time.

Resources:

 

New York

Possession/Use Limits: The marijuana that may be possessed by a certified patient shall not exceed a thirty-day supply of the dosage as determined by the practitioner, provided that during the last seven (7) days of any thirty-day period, the certified patient may also possess up to such an amount for the next thirty-day period.

Grow Limits: Home cultivation is not permitted.

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Oregon

Possession/Use Limits: Recreational marijuana consumers 21 years of age and older may possess up to eight (8) ounces of usable cannabis. A registered Oregon medical marijuana patient may possess up to 24 ounces of usable marijuana.

Grow Limits: Recreational marijuana consumers 21 years of age and older may possess up to four (4) plants per residence. A registered Oregon medical marijuana patient may possess up to six (6) mature plants, which must be grown at a registered grow site address. Caregivers, or OMMP growers, cannot be growing for more than four (4) patients at a time, and cannot grow more than six (6) mature plants per patient.

Resources:

 

Rhode Island

Possession/Use and Grow Limits: A patient cardholder who has in his or her possession a registry identification card shall not be subject to arrest, prosecution, or penalty for the medical use of marijuana, provided that the patient cardholder possesses an amount of marijuana that does not exceed twelve (12) mature marijuana plants and two and one-half (2.5) ounces of usable marijuana. Said plants shall be stored in an indoor facility.

A primary caregiver cardholder, who has in his or her possession, a registry identification card, shall not be subject to arrest, prosecution, or penalty for assisting a patient cardholder, to whom he or she is connected through the department’s registration process, with the medical use of marijuana; provided that the primary caregiver cardholder possesses an amount of marijuana that does not exceed twelve (12) mature marijuana plants and two and one-half (2.5) ounces of usable marijuana for each patient cardholder to whom he or she is connected through the department’s registration process.

A cardholder shall be allowed to possess a reasonable amount of unusable marijuana, including up to twelve (12) seedlings, that shall not be counted towards the limits of this section.

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Vermont

Possession/Use Limits: A registered patient may comply with possession limits and possess up to two (2) ounces of usable marijuana. A designated registered caregiver for the purpose of assisting a registered patient may possess up to two (2) ounces of usable marijuana.

Grow Limits: A registered patient may comply with possession limits and cultivate no more than two (2) mature marijuana plants and seven (7) immature marijuana plants (if the registered patient elects to cultivate marijuana). A designated registered caregiver for the purpose of assisting a registered patient may cultivate up to two (2) mature marijuana plants and seven (7) immature marijuana plants for the registered patient who has named the person to serve as caregiver. The collective possession amounts between the registered caregiver and the registered patient must meet the total possession limit.

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Washington

Possession/Use Limits: As part of authorizing a qualifying patient or designated provider, the health care professional may include recommendations on the amount of marijuana that is likely needed by the qualifying patient for his or her medical needs. If the qualifying patient or designated provider with an authorization from a health care professional has NOT been entered into the medical marijuana authorization database, he or she may not receive a recognition card and may only purchase at a retail outlet.

If the health care professional does not include recommendations, when adding the qualifying patient or designated provider to the medical marijuana authorization database, he or she shall enter into the database that the patient may obtain at a retail outlet holding a medical marijuana endorsement a combination of the following:

  • Forty-eight (48) ounces of marijuana-infused product in solid form;
  • Three (3) ounces of usable marijuana;
  • Two hundred sixteen (216) ounces of marijuana-infused product in liquid form;
  • Twenty-one (21) grams of marijuana concentrate.

Grow Limits: The qualifying patient may also grow, in his or her domicile, up to six (6) plants for the personal medical use of the qualifying patient and possess up to eight (8) ounces of usable marijuana produced from his or her plants.

If the health care professional determines that the medical needs of the patient exceed those amounts, the health care professional must specify on the authorization that it is recommended that the patient be allowed to grow, in his or her domicile, up to fifteen (15) plants for the personal medical use of the patient, and may possess up to sixteen (16) ounces of usable marijuana in his or her domicile.

If the qualifying patient or designated provider with an authorization from a health care professional has NOT been entered into the medical marijuana authorization database, the qualifying patient may grow, in his or her domicile, up to four (4) plants for the personal medical use of the qualifying patient and possess up to six (6) ounces of usable marijuana in his or her domicile.

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