Starting Marijuana Seeds In Solo Cups


Buy Cannabis Seeds Online

Beginner’s how to guide to germinating cannabis seeds, plus early seedling stage of cultivation. Specific to outdoor autoflower growing in soil. Transform Ordinary Solo Cups Into a Hybrid Hydroponic/Soil Plant Booster: If you have ever attempted to start plants indoors before your last frost, you probably know what it is to get a root bound plant. No matter the size of your growing container, it does not take the roots too long to find its outer boundaries. This m… Categories: Setup. Seedling. Grow Question by MagicPlants17. Best place to get answers to your grow questions. Worldwide community of enthusiast growers will share experience.

How To Grow Cannabis #2: Germination and Seedling Stage

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.

Ok, so 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


White paper towels (no dyes or patterns)

Liquid seaweed (I used Neptune’s Harvest)

Glass measuring cup (something with a spout)


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.

See also  Grasso's Green Strain Of Marijuana Seed

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…



pH Meter (I used this)

pH Adjusters (General Hyroponics pH Up/Down, or distilled white vinegar)

LED Grow Light (I used something basic 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).

See also  Grease Monkey Weed Seeds

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.

Transform Ordinary Solo Cups Into a Hybrid Hydroponic/Soil Plant Booster

Introduction: Transform Ordinary Solo Cups Into a Hybrid Hydroponic/Soil Plant Booster

If you have ever attempted to start plants indoors before your last frost, you probably know what it is to get a root bound plant. No matter the size of your growing container, it does not take the roots too long to find its outer boundaries. This method uses the benefits of hydroponic growing to keep those roots thriving, while preparing your plant to live in soil.

Step 1: Watch the Video

This Youtube video leads you through all of the steps of converting red solo cups into an outstanding hydroponic/soil planting solution.

Step 2: Keep a Couple of Your Old Solo Cups

You can use new ones of course, but why not get some use out of them first. We don’t judge you based on what was in the cup prior to starting the project.

Step 3: Let’s Put Some Holes in the Bottom of One Cup

Or I have found you can easily do up to five of these at a time, but you will want one hole-free cup for every cup into which you put holes. You can use a nail, scissors, box knife, any number of things to cut your cups; however I find that for the smoothest process and the least chance of unintentionally cracking out your cup, warming a screwdriver over an open flame for about a minute and then pushing down with some force and melting through works best.

Step 4: Put Potting Soil Into the Cup That Has the Holes

I have used straight compost for this before as well. Whatever growing medium you would normally use for a potted plant should be used here.

See also  How Long Do Cannabis Seeds Last

Step 5: Place Inside the Solo Cup Without Holes

Step 6: Plant Your Seedling Into the Cup

It is time to put your seedling into the new creation. Plant it like you normally would when transplanting a seedling into a larger pot. Then give it a good initial watering. There are drainage holes in the inner cups, so your plant should not get water logged, and the outer cup will prevent water from spilling out.

Step 7: After a Good Initial Watering, Water Sparingly

You want those roots to seek out the holes in the bottom. If the soil goes completely dry and there are not yet roots in the bottom, make sure to water to keep your plant alive, but as soon as you see a root peeking out the bottom of the inner cup, quit watering from the top.

Step 8: Add Hydroponic Solution to the Outer Cup

Once you see that root peeking through, add hydroponic solution to the outer cup. The roots will thrive, and the plant will get tons of nutrients from the hydroponic solution. Your plant will grow as if it was in a much bigger pot, and be very health to transplant outside later.

Solo cups vs clear plastic cups for seedlings

I’m gonna plant sprouts in solo cups, but thought it might be cool to use clear plastic cups (to see when roots reach the edges). Would it be bad to use clear plastic cups? Maybe the roots/soil won’t like the light idk?

If you use see through just put a cooler cup on it if you got one that slides over it easily. Good luck and happy growing :evergreen_tree::evergreen_tree::evergreen_tree::facepunch:

Correct, plant roots do not like light and will die if exposed to it for a prolonged period. Roots grow under the ground – a dark environment, period.
Hope this helps. Organoman.

Debatable when soil vs. DWC lol I first started in water bottles with the tops cut and transplanted when the roots were spaghetti around the bottle :expressionless: lmao they love it, I love. debatable :the_horns::facepunch::ok_hand::+1:

Opaque cups. Roots hate Light. Trust me I am a dwc grower and well all know the troubles of root stress if the roots are exposed to light they can burn, which can in turn cause stress to your lady. It also attracts algae when watered which can in turn lead to much worse things in my opinion anyway. Though I will end with what I always say on this site. There is no “Correct way” to cultivate a cannabis plant. every grower has different methods that work for them. So dont take my advice as gospel use your common sense and I’m sure you will excel with the new seedlings 🙂 Best of luck for all your future harvests 🙂 Peace out

How useful was this post?

Click on a star to rate it!

Average rating 5 / 5. Vote count: 1

No votes so far! Be the first to rate this post.