Wool cubes for starters

Hi guys, I’m just a beginner grower but I have had a decent grow with some blueberry plants. I started them in wool cubes and literally left them in there as I grew a few in hydro buckets and a couple in soil. I had decent success other than some ph problems I eventually fixed.
So having said that. Feeling cocky, I decided to try my hand with some maui wowie fem seeds and sprouted them in wool cubes just like I did with the blueberry plants. I initially soaked the cubes with the seeds inside and watered every 12 hours to keep cubes wet. I put them under a blurple light with 18 hours on and 6 off. But after the seedlings reached about an inch, they just laid over and wilted. Did that with 2 seeds. What’s different about growing these and the blueberries? TIA.

@Lednut what are the temperatures and humidity in your grow space? What you described sounds like what’s called damping off. It’s caused by over watering and higher humidity allowing fungus to breed in the root zone. It happens easier when coupled with lower night temps too.

Seedlings are especially sensitive to damping off. If you don’t aerate your waterings and feedings to allow more oxygen to the root zone you greatly increase the risk of root rot and damping off when you over water.

Damping off is when you water too much and keep the substrate too wet which allows fungus to start growing and suffocate the newly forming root system. The plant just falls over and often the leaves will curl under too. Some plants are more prone to these fungal infections than others.

As far as a genetic reason for the difference between Blueberry and Maui Wowie in your set up there really isn’t much of one aside from one being indica and one being sativa. Blueberry can handle colder night temps though where as Maui Wowie can’t. If it dropped under 60f for more than a day or two that’s enough to kill Maui Wowie seedlings in a high humidity environment even though they are more resistant to molds, mildews, and other humidity issues compared to the Blueberry. So it was either damping off or cold shock in my opinion.


Thanks for the response. Temperatures are in the mid 70s and humidity is fairly low, at I’d say around 50ish. I feel like I watered the cubes for the Maui wowie the same as I did for the blueberry plants. I have the cubes sitting in clay pebbles so the roots should be getting some air. Night temps are the same as I’m growing in my home. I also have the lights on them at night also so that should be keeping them a little warmer as well. Lights are about 12 inches above. I’m using a blurple light to start them but do you think I might have a better chance using HPS bulbs instead?

@Lednut did you sterilize everything in your environment before planting and did you use gloves and sterile tools? All it takes is one spore to contaminate a seed.

If it was cold and you had no way to control temperature I would say yeah use some metal halide or hps but temps in the 70s are just right.

Those blurple style leds will work fine to grow. It isn’t the light that’s the issue.

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@MDBuds No didn’t sterilize anything. Used in same environment as previous plants. Used a new wool cube of course but same clay pebbles as before without sterilizing. Do you recommend anything to sterilize the clay pebbles?

@Lednut I usually sterilize with either h202 or white distilled vinegar. You definitely want to sterilize those pebbles before every new grow because they’re breeding grounds for fungus and bacteria. When I use them I’ll even sterilize them a few times through the grow using h202 or vinegar with some water for ph down when needed. Misting the pebbles with liquid kelp works too during the grow because it raises the surface ph of the pebbles so bacteria and fungus can’t breed.

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@MDBuds Much appreciated! Never knew that. Hopefully that does the trick.

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Most Likely over watered the plugs. I’ve began using them recently. I use h202 and distilled water to soak the seeds for a few hours first. While doing that I make up a gal of light nutrient feed.
By like I mean line 3 ml grow 3 ml micro, 2 ml bloom, 1 ml silica, 2 ml calmag and after calmag I mix in 0.5 ml of roots excelerator. I then PH then adjust the pH down to 5.7, I let the cubes soak in a bowl with nutrient mix for a few hours and if I dont forget after about 4 + hours I will squeeze the cubes till they aren’t dripping or soaking wet and I’ll take a seeds and put them in the cube . I then put the cubes in a clone/seed starter tray and dome . I make sure there is about a half inch of that nute mix in the tray and will sometimes tape 2 ends of tray to keep secure. You ideally want your environment in that dome to be
80° and Rh at 68% to 74% and not in direct light. You can also make it a but easier by using 1gal ziplock freezer bags. I blow into the bag while zipping it up so it makes a balloon type effect and within a day or two I always have roots

in the picture there are 8 white Larry dragon seeds from Dragonsflames and 6 of 8 have popped in under 24 hrs.


Thanks Luckily! That’s some quick root time. Yeah, I don’t see anything wrong with giving your seedlings a little nutrients to start their lives off with. And yeah, it could be a combination of over watering the seedlings and like MDBuds said quite possibly the clay pebbles not being sterilized. I’m gonna sterilize the pebbles today and try again.

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Awesome. I’m sure you’ll see sprouts soon. Good Luck :smiley::smiley:

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