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starting cannabis seeds in a dwc

How to Start From a Seed in a DWC Bubbler

The most delicate stage of development in a plant is germinating the seed into a seedling. If there is not enough water, the seed doesn’t start. If there is too much water, the seed dies. The answer is in using the DWC Deep Water Culture hydroponics method of starting your seeds. A DWC is relatively cheap to build if constructed correctly and provides an oxygen-rich environment for your seedlings. Using the DWC system avoids the insects that come with using soil or other media for growing seeds in.

Place duct tape over sides and bottom of the plastic container or bucket. The goal is to prevent light from entering the interior of the container and causing algae to grow. If the container you chose is a dark color and does not allow a lot of light to penetrate the sides or bottom, you can still apply duct tape to prevent what little light there is from penetrating and causing slow algae growth, which will kill the roots of your seedling.

Drill a 1/8-inch hole about 1 inch from the top of the container. The hole should be located in the back portion of the container. Insert the black air hose into the container through the drilled hole and connect the air stone to the black hose on the inside of the container. The air hose can be purchased from any pet store or aquarium supply.

  • Place duct tape over sides and bottom of the plastic container or bucket.
  • The hole should be located in the back portion of the container.

Drill a 1-3/8-inch hole into the lid of the container, place the lid on the container and set a similar sized net pot into this hole. Note where the bottom of the pot rests, as the pot should not reach all the way to the bottom of the plastic container. There should be enough room in the container so that the net pot rests just below the water level. You don’t want to have the developing roots saturated, just nice and moist.

Remove the lid from the container and fill with water up to the level just below the net pot. The air stone should be heavy enough to stay submerged, if it is floating you can use some clean stones to weigh it down.

Connect the other end of the black hose to the air pump and plug it in. Look inside the container for the bubbles to make sure the air pump is working. Replace the lid and push down firmly to lock the lid in place.

  • Drill a 1-3/8-inch hole into the lid of the container, place the lid on the container and set a similar sized net pot into this hole.
  • Remove the lid from the container and fill with water up to the level just below the net pot.

Insert the seed into the plant growth media. Rock wool or clay pebble medium is one option, but that requires a preparation washing of the dirt and dust particles to get your plant growth media clean. The other option can be found in hydroponics stores and online and resembles a light foam material. One company that developed this type of media is called the Sure to Grow. It is available in different sizes and can be used for seeds or propagating cuttings from existing plants. They call this media the Storm Series or Hail.

Place the plant media into the net pot with the pump running. Wait about seven to 14 days for the roots to begin to develop. At this point you can add a minimal amount of nutrients to the water so that the roots continue to grow. If the seed you are starting is of a larger plant, you will need a support system to allow the plant to continue growing. Which nutrients you add depends on the type of seed you are germinating.

  • Insert the seed into the plant growth media.
  • Rock wool or clay pebble medium is one option, but that requires a preparation washing of the dirt and dust particles to get your plant growth media clean.

Watch the water level and add more as needed. Keep the level at the same point and make sure the air pump is running constantly, generating the oxygen the plants need to survive.

Seed Starting In my DWC System

So, I'm not sure why, but I suck with seed starting systems and trays. So, I decided to try something different and I was wondering if anyone here has tried this. I made a simple DWC system from a rubbermaid tub. Once I had the net cups in place and filled with hydroton, I put seeds in each one. The seeds are in the center of a small ball of toilet paper that I keep moist every day. I just did this a few days ago and I'd like to know if I'm wasting my time so I can move on to something else. Anyone else tried this (or something similar) before?

Also, is it a horrible idea to introduce seeds to nutrient solution? Should I wait until they completely sprout to do that?

Thanks for any help!

A healthy seed will have enough nutrients to get the seed started and growing the first leaves, so I say back off on the nutrients until it's developed a bit of a root system and a real plant.

My main problem with starting seeds directly in a DWC would be ensuring proper moisture levels. Have you considered trying the paper towel technique? (double/quadruple folded wet paper towel with seeds between, put inside plastic bag and place warm until you see seeds sprout)

Starting seeds in DWC

when i was using rockwool i waited until there was a good amount of roots poking out the bottom of the cube and put an inch layer of hydroton on the bottom of the netpot and place the cube on top of that and filled in the sides.

Top fed for a few days until I saw a root sticking out the bottom. I would water the surface around the cube. Rockwool gets highly saturated to the point where no oxygen is left in the cube.

Brock Logan
New Member
Active Member

If you are going totally media free, use vermiculite. A user on here suggested it. It works great, I use Solo cup half full(then you can bag them to keep humidity up, remember to poke some holes and bottom water), you can grow it in cup for quite a while then just dip in water and wash off the vermiculite when ready to put into DWC.

And no, if your rockwool is sitting in water your seedling will die, the water inside the rockwool cube has no way to get oxygen, you must let it dry out and water it again, which is another problem, letting it get to dry. I found vermiculite method easiest and use it for taking clones sometimes also.

Hawzzy
Member

Good advice. ive done it 3 ways. now. first with peat pellets. germinate, poke it into pre moistened pellets place in tray under dome, mist daily, let pellets dry a little, wait for multiple roots then plant in net cup with media ass mentioned above under low light.. I DONT RECOMMEND BECAUSE THEY HOLD TOO MUCH WATER. but good for dirt planting.

Rockwool. soak in phd water overnight or 24 hours. germinate seed. squeeze out rockwool slightly if saturated, poke root end of popped beaner into the rock wool and place in humidity dome and tray as above. Works good BUT I found it tends to grow a lot of algae and crud if exposed to light. and can hold too much water and rot the stem.

I use a bubble cloner to root my clones and once they have good multiple 3-6 inch roots (depending on my timing) I just carefully drape them in the net pot and carefully fill in with hydroton or whatever. I find if I can wait for 6 inch roots, i can put them straight down thru the bottom of the net cup and fill with hydroton.

That being said. I havent tried it with a seedling yet. might try to dangle one in the cloner and see if it roots or the vermiculite ane hand water idea is good.

My very fiirst dwc grow. I took 4 dirt planted seedlings and rinsed them really well soaking in a sink then planted em in hydroton. not recommended tho.

Ive rambled sorry.

Anon Emaus
Well-Known Member

Everyone makes this process more work than needed. I have my water level 1/2-1" below net pot with water bubbling, put seed in moist rapid rooter, set rooter on 1/2-1" of hydroton(fill remaining hydroton in net pot around rooter). Bubbles will wick water thru hydroton to rooter to stay moist. If you use a hot light that drys the rooter more than your liking remoisten. All done, let it grow.