How To Grow Cannabis #2: Germination and Seedling Stage
A good starting point for learning how to germinate cannabis seeds, but if you’re growing autoflowers, don’t follow Part #7 of this series so closely (it’s specific to photoperiod plants)…
Disclaimers: NOT FOR SALE OR TRADE. The following post features content about cannabis cultivation and other related substances that are illegal under federal law as well as under state law in certain states. This content has been produced by Thunderbird Disco—located in the Commonwealth of Virginia—for educational and entertainment purposes only. All cultivation described below was completed in accordance with Virginia law as authorized in § 4.1-1101 Home cultivation of marijuana for personal use; penalties.
NOTE: If you missed Part 1 of this series, feel free to check it out. For purely educational purposes, I highly recommend Homegrown Cannabis Co., which has terrific video content and information on seeds, as well as I Love Growing Marijuana, which has an excellent 70-page “Grow Bible” eBook for beginners and plenty of information on autoflower seeds.
But ok, let’s say you’ve got some cannabis seeds that you found on the side of the road or were maybe gifted from a friend in the same state. Nice job!
The next step is to germinate these seeds. Again, I’m growing outdoor, in soil, and was gifted three autoflower strains, so everything below is specific to those parameters.
If you’re growing outdoors and want to maximize your time, plan to start germination a few weeks before the last spring frost date in your region, so by the time the weather is warm enough and risk of frost is gone, you’re ready to move these ladies outside.
This won’t all make sense yet, but here’s a handy dandy week-by-week outdoor autoflower cannabis growing cheat sheet for all your watering, nutrient and general maintenance needs
MATERIALS
White paper towels (no dyes or patterns)
Glass measuring cup (something with a spout)
Purified water
Glasses
Dinner plates
Labeling tape
TIME: 2-3 days
WEEK ZERO: GERMINATION
Step 1: First Soak
Pour purified water into measuring cup and add just a drop of liquid seaweed. Stir. If you’re growing multiple strains, don’t mix all the seeds together in one vessel! Label different glasses with the different strain names and pour some seaweed water into each glass. Place your seeds in this water and let soak for about 24-48 hours in a warm, dry, dark place.
Step 2: Second Soak
Add another few drops of liquid seaweed to some purified water. You’re going to make this little wet paper towel sandwich with your seeds in the middle (follow this video). Stack 2-3 paper towel squares, fold in the corners to make into a diamond, place it on a dinner plate and then wet it down with seaweed water. Gently spread your soaked seeds onto this paper towel (again, keep the strains separate, and transfer the label from the glasses to the dinner plate). Now add another stack of 2-3 folded paper towels on top, and again wet it down. You want this stack to be wet but not soaking (no standing water on the plate). Plan to leave this for another 24-48 hours.
Step 3: Keep Moist
Don’t let the paper towels totally dry out. Check every 8-12 hours or so and add more seaweed water as needed.
Step 4: Check for Taproots
After 48 hours, very carefully peel back the paper towel and check to see if there’s a taproot coming out of each seed. The root is likely a bit stuck to the paper towel, so go very slow and make sure you don’t damage this sprout while you’re peeling off the paper towel. If you see taproots, go on to the next phase. If not, let the seed sit in the moist towel for another day or two.
Once you have your taproot showing…
WEEK ONE: SEEDLING STAGE
MATERIALS
3- or 5-Gallon Grow Bags (I used Opulent Systems 3-gallon)
Seed Starting Mix (I used Fox Farm Light Warrior)
Pre-Amended Potting Soil (I used Fox Farm Ocean Forest)
pH Adjusters (General Hyroponics pH Up/Down, or distilled white vinegar)
Saran Wrap
Binder clips
LED Grow Light (something basic like this or slightly more advanced like this)
Hydroton clay pebbles (optional, like this)
Seedling Heat Mat and Thermometer (optional; like this)
NOTE: You’ll find some videos online (like this one from Homegrown) that recommend first planting germinated seeds in Solo cups and then transplanting to larger pots or grow bags…but this is only for photoperiod plants. I accidentally did this with my seeds and the transplant process either killed or at least stunted my autoflower plants, which aren’t as robust and don’t have as much time to recover from the stress of transplanting. Plus, it’s an annoying extra step. Having tried it both ways, I highly recommend planting germinated autoflower seeds directly into the pot or grow bag that they’ll live in forever. You can see the side by side comparison below.
Step 1: Prepare Grow Bags
Add a 2-inch layer of Hydroton to the bottom of your grow bags (optional, but helps strike a balance between good drainage and moisture retention). Fill bags most of the way with Fox Farm Ocean Forest super soil (a favorite among growers you’ll see abbreviated as “FFOF”).
Don’t press down or pack the soil in there, keep it light and fluffy.
Step 2: Add Seed Starting Mix
Scoop out a small bowl’s worth of FFOF and in that center hole add in some of the Light Warrior seed starter mix. This stuff is a little lighter and has less nutrients so it won’t “burn” the tender sprout. But as the taproot grows and the roots begin to establish and stretch out, they’ll reach the “hotter” FFOF mix once they’re strong enough to handle it.
Step 3: Prepare pH-Adjusted Water
You can take your chances with water straight from your tap, but it’s most likely not in the ideal pH range of 6.0 - 7.0 that autoflower cannabis plants require. Proper soil pH is what determines how well your plants can uptake nutrients, and anything too far out of the optimum range will be like they’re drinking through a pinched straw.
Use your properly-calibrated pH meter to test your tap water. Mine was in the 7.5 range, so I needed to adjust down. You can use professional products (like these) but I just added a little distilled white vinegar to make the water more acidic and bring the pH down. You only need a tiny bit, like 1-2 ml per gallon of water, to shift the pH, so go slow and see what it takes to get close to that sweet spot of pH 6.5. You’ll be using pH-adjusted water throughout the grow process, so might as well start practicing this step (don’t make the mistake I did, thinking this was a complicated an unnecessary step; bad pH can lead to all kinds of problems).
Step 4: Moisten Soil in Grow Bags BEFORE Adding Seeds
Saturate your grow bags with this pH-adjusted water to moisten the grow medium. Do this before adding the seeds, or else you risk disturbing the seed or having it float away.
Step 5: Add Germinated Seeds
Gingerly place one germinated seed in the center of each wet grow bag (the area with the Light Warrior Seed Starting Mix), taproot facing down. Just barely cover it with soil. Make sure you continue to track which seeds/strains are in which bags, adding plant labels to the bags or to the soil. Place plastic wrap over the top of the grow bag and secure with clips. Poke a couple holes in it to create a nice warm terrarium kinda thing.
Step 6: Add Light
Place these grow bags under the LED grow lights turned on 24 hrs/day, with the soil about 8-12 inches away from the bulb. After about 48 hours, check to see if the seeds have sprouted. Once you see little green leaves poking out from the soil, remove the plastic wrap from the bags. Seedlings crave warmth at this stage, so if the bags are in a cooler spot consider using something like this Seedling Heat Mat and Thermometer setup to warm it up a bit.
Step 7: Leave Them Alone!
Seedlings need VERY little at this stage other than 24-hr light. If you think you should water them, probably don’t! If you think you should feed them with nutrients, probably don’t! The magic is in the seed itself and the existing wet nutrient-rich soil in the bag will be sufficient for 2-3 days. Only give it a very little bit of pH-adjusted water every few days, after the soil feels dry. I killed or stunted a bunch of plants by watering them too much.
Okay, then what?
Click Here—> HOW TO GROW CANNABIS #3: VEGETATIVE STAGE
