The definitive guide to growing marijuana in Hawaii under the State’s Medical Cannabis Program. Learn how to grow weed in Hawaii legally—from getting your 329 card to building a grow site and starting cannabis plants at the right time.
Hawaii’s Medical Cannabis Program allows registered patients to grow up to 10 plants at the patient or caregiver’s residence with up to 4 oz. of usable cannabis jointly.
Get Medical Marijuana Card Hawaii (329 Card)
First step is to get your State of Hawaii 329 Medical Cannabis registration card.
The process is fairly simple:
1. Find a local medical marijuana physician. You can search Google Maps for MMJ doctors nearby. If you are on the Big Island or Kauai, Hawaii Compassionate Care is a good choice.
2. Schedule an appointment to get diagnosed. To qualify as a patient, you must have an eligible debilitating medical condition.
3. Fill out the forms. As of 2016, all applications must be submitted online at eHawaii.gov. There is a non-refundable $38.50 registration fee.
4. Submit and wait. Since 2019, an electronic registration card is provided, eliminating the wait time for a hard copy 329 card by mail.
Where to Grow Medical Marijuana in Hawaii?
Your single grow site must be designated with DOH when registering or by notification of change—the grow site address needs to appear on your 329 card.
Both indoor and outdoor cultivation is done every month of the year in Hawaii.
For outdoor growing, you’ll want an area with plenty of sunlight, access to water, and ideally, a light breeze. If the site is grown in with invasive species, consider clearing them out.
Depending on where you are in Hawaii, there may be soil to amend and grow in. Otherwise, you can buy potting mix or blend your own. Something similar to a True Living Organics mix may be reused for multiple grows.
A simple greenhouse built with PVC and clear plastic can help protect your buds from the rain. However, it will bring gray mold and powdery mildew problems without enough airflow. To solve this, keep parts of the greenhouse open, use fans or install a full ventilation system.
Nutrients are important for growing healthy plants. Hawaii’s soils are often low in Nitrogen and Calcium. Learn a few tricks to save money on nutrients from our marijuana fertilizer guide.
Slugs damage cannabis plants and are even dangerous to humans due to the rat lungworm disease endemic. Clear out any brush on the ground around your grow site that could be habitat to slugs. You may consider using organic slug bait.
Once your grow site is prepared and ready to grow, it’s time to get some plants. You can start from seed, clone, or use established plants.
Marijuana Seeds Hawaii
Buy marijuana seeds in Hawaii from online seed banks and local breeders.
Visit the Mold Resistant Strains homepage for a wide selection of marijuana seeds for sale, from landrace strains all the way to high yield hybrids and mold resistant outdoor strains.
Refer to this list of the Best Marijuana Seed Banks for trusted cannabis seed sellers that ship to USA, including Hawaii.
Germinating your seeds in the Hawaiian sunshine will produce varying results depending on the time of year. Hawaii’s subtropical growing season is different than cold climates in this regard.
Hawaii’s Growing Seasons
Hawaii has two growing seasons, called “long season” and “short season”. Simply put, the plants grow faster in the long season and slower in the short season.
This is because cannabis reacts to seasonal changes—a trait called photoperiodism. Photoperiod plants grow and bloom according to the light hours seen per day.
Indoor growers can manipulate this trait to control the size and life cycle of their plants. In essence, they control the seasons with grow lights.
Outdoor growers are subject to the sun’s daylight schedule as seasons change. This is why you’ll hear Hawaiian growers talk about the best time to start seeds.
The long season is the same spring-to-fall growing season that the rest of the northern hemisphere is on.
Long season is the best time frame to grow cannabis outdoors in Hawaii for maximum yield.
Like many other crops, cannabis plants will use spring for vegetative growth and summer/fall for blooming.
You can start seeds any time from spring to mid-summer to grow during long season.
Grow Indicas Long Season
Start indica seeds and indica dominant hybrid seeds from April until July for long season growing. The lucky time for us is on the dark of the moon in May.
Indica seeds sprouted before spring might not adjust to the long season—they’ll end up finishing early in June or July. The buds don’t form as dense then as they will during late summer/fall. That’s why it’s usually better to start the fast flowering indicas after the sativas.
On the flip side, starting indicas too late will result in the plants blooming into winter, when yields are reduced due to low light hours.
Grow Sativa Long Season
Start sativa seeds and sativa dominant hybrid seeds as early as February until May to for long season growing. The dark of the moon in April seems to be a good time for sativa dominant hybrids.
Sativa seeds sprouted too early in the season may get old and woody (what we call “pepper pot”) by the time they are ready to harvest.
On the other hand, starting sativa strains too late could bring the plants blooming through winter and re-growing in the spring as a mess of stretchy buds.
Grow Hybrids Long Season
50/50 sativa/indica hybrids, or breeds close to that ratio, tend to grow more like an indica than a sativa. So a safe germination time frame is from March until early June.
Long Season Harvest
Cannabis plants growing in the long season are typically ready to harvest from August to November. Each strain and phenotype reacts differently. Some long flowering sativas will even keep budding into winter, such as Thai strains. Here are two things to consider before planting:
- Everyone is going to have bud for sale in the fall, so you can stay ahead of the market with fast flowering strains that finish in August.
- Alternatively, you could go big with mostly or pure sativa strains. These plants will grow larger and take longer to mature but can yield enormously.
The short season is unique to subtropical climates. You can harvest marijuana buds throughout winter, spring, and early summer.
Normally, the plants grow slower in short season.
This is because of decreased daylight hours. At under 11 hours in December, it is lower than even a flowering room indoors, so starting seeds at this light cycle makes a strange predicament for the plants to decide how to grow.
Grow Indica Short Season
While they do grow fast, most pure indica and indica dominant strains don’t really get enough light hours in the winter to grow big. A lot of growers end up with what’s known as the lollipop: a stick in the ground with a single bud.
The best bet for indicas is to start seeds around late summer to fall. That way, the plants can get bigger than if they were started over the winter. As we get into December, it’s really hard for the seedlings to thrive—they’ll just sit there and not grow.
Grow Sativa Short Season
Many sativa strains come from similar subtropical climates, such as South East Asia, Africa, and Central America. Over generations of inbreeding, the plants have adapted to growing in short seasons and actually get big!
However, most sativas are quick to re-veg in the spring. That means all of the buds will stretch out and end up rotting on the plant. Light deprivation techniques are a solution to this. As a rule of thumb, the only time you’ll want to grow sativa strains naturally in the short season is if they’ll finish before March.
Grow Hybrids Short Season
Hybrids are perhaps the most rewarding option for short season cannabis growing. Slightly sativa dominant, 60/40 strains perform well. The sativa genetics aid the plant vertically, while the indica genetics help prevent too much vegetative morphing in the spring.
Grow Lights for Perpetual Outdoor
Get the best of both worlds—use indoor grow lights on your outdoor crops. If you give the plants a total of at least 16 hours per day, they will stay in vegetative growth status, and won’t start flowering until you stop giving them that extra light.
This growth hack lets you control the plants just like an indoor grower does, leaving size and bloom cycle up to you.
The plants can be grown outside during the day and soak up the sunlight for free. Then before sunset (or alternatively, before sunrise), put them under grow lights for a few hours, or the whole night!
Indoor-Outdoor Grow Light Method
1. Set up a grow room or put lights outside: You can have your plants in pots and carry them into your grow room with lights, or make a dedicated greenhouse/covered outdoor area for putting grow lights over plants in the ground. Flip the lights on as sunset approaches.
2. Calculate the daylight hours and add up to 18: You can check daylight hours online at timeanddate.com/sun. Then add extra light hours to it. You’ll want to be at 18–24 hours of light for fastest growth.
3. Keep on the lighting schedule daily: Interruptions may bring plant mutations and hermaphrodites. Even missing one day should be avoided if possible.
4. Induce flowering: Stop providing extra light, and the plants will start their bloom cycle. You can refer to the strain’s flowering time, if listed, to estimate harvest dates.
That’s it! Now you can harvest da crip kine pakalolo (dank bud) every 30 days, 45 days, 60 days, or whenever. Mark dates on your calendar to cut new clones or plant seeds, transplants, flowering, and harvest.
Are LED Grow Lights worth it for Hawaii?
LED grow lights are a good option for many cannabis growers, especially with the high electricity price in Hawaii. LED grow lights use less electricity than standard HID grow lights while giving off just the right type of light needed by plants to grow. The secret to these highly efficient LED grow lights is their optimized red and blue light spectrum—frequencies most absorbed by plants.
View our list of the best LED Grow Lights this year for grow light recommendations.
Hawaii Cannabis Culture
Hawaii Cannabis Organization, Hawaii Cannabis News—Hawaii cannabis education, events, and community.
Hawaii Cannabis Expo—A yearly event. Connect with the local cannabis community.
What are your favorite strains and methods for growing marijuana in Hawaii? Leave your comments below. Aloha!