How to use rooting cubes

Good morning all. Time for another noob question. So I purchased one of those seedling things. Its a plastic tray with a tray that sets inside with 50 squares for rooting cubes a plastic dome with a section for a T5 Tube an a heating pad below.

I am using root riot cubes an am sucking major at this. I place the seed point down into the cubes, leave the heat pad on, leave the light on, keep the little vents closed, an mist it once every few days. They shrink up and dry out an no seed X_x. What the heck am I doing wrong here?

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Very important step to using cubes/rooters is to keep the medium damp not soaking nor allowing it to completely dry out. There is a very fine line between the two.

I like to soak rooting mediums a couple days prior. If using cubes wet them thoroughly then wring them out mostly. Leave enough moisture for a few days. I like to do this early to see how long the moisture lasts. It should be still damp by 2-3 days later easily.

Drowning seeds is a VERY easy thing to do. I’ve killed at least 4 this go round at year 3. Dont be discouraged. Tweak and try again. Maybe with some cheap bagseeds for practice germinating.


I’ve started all of my ILGM seeds using the following method. I’ve been very successful. Only one seed has not popped out of 20ish seeds.

I soak my seed in a cup of water with a splash of hydrogen peroxide for 18-24 hours. The cups are on a germination heating pad.

I then transfer the seed, cracked or not, to a wet paper towel. I use the water from the cups to moisten my paper towel.

I then take the paper towel and put it in a plastic bag. I roll the opening of the bag inward to keep it open.

I normally have tails about 20-24hrs after moving them to the paper towel.

With that said, I decided to start a bunch of vegetables using rapid rooters and a dome. It worked great!

Then I tried marigolds the same way. They took off better than the veggies!

I may try a cannabis seed this same way in the near future

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I use ur method Neo… well used too. Eliminated the napkin last to times ive germ’d… horrible rates now. Going back to my paper towels

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If it’s the tray with a hole in bottom of each spot it is what I use.

Always add water to lower tray being careful NOT to have water above holes ( this will soak cubes )
With just enough water in lower tray it will keep everything moist and humidity nice and high.

Always germinate first to get a tail on seed then place in root riot plugs.
I place seeds in a clear glass with distilled water I buy by the gallon at local grocery. Place glass in tray with heat mat on and no light , has to be dark. Seed will crack and tail shows within 48hr usually. Once tail is about 1/4 to 1/2 inch it’s ready for the root riot plugs.

I take a steak knife and cut plug down side so I can fold it open and add seed with taproot down then place in the tray. I do not soak plugs or add water at first. I do add a half a teaspoon of water as needed to top of plug being careful to add at edges.
( usually once a day if cube looks dry )
And light on once seeds are in root plugs.

Once again be careful not to add to much water to bottom of tray. At least mine has space for water. It is extremely tiny gap. Possibly 1/4 inch if that. If tray is not level be sure starter plugs are at the higher side of it so water stays away from them. They sponge up the water if it hits them and damps them off killing them. So just a small amount of water in tray.