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Rockwool vs. Rapid Rooter

W

wordwiz

Now that the upstairs has cooled off (it was 115 some days this summer!) my hydroponic tomato plants are looking good. I'm convinced I can run a small operation this winter in my basement (~40 tomato plants) and perhaps do it year-round, adding more sites as I go.

But as Dirty Harry (Clint Eastwood) said, "A man needs to know his limitations." One of my very short shortcomings is germinating seeds for use in hydro. If I sow 30 tomato or pepper seeds in potting mix, I expect and usually do have at least 25 that end up producing fruit; that is they germinate and survive transplantation, as well as go on to grow. But with hydro, 30 seeds will mean maybe 10 plants, if I get lucky. :(

Perhaps I'm trying to apply soil techniques to hydroponics (keep the rockwool moist, the area at about 85 degrees until the seeds sprout, put them under good lights once they germinate) or maybe I'm using less than ideal media. Potting mix gives me great germination rates and strong seedlings, but the transplant success rate is less than 50 percent. That rate is much better with rockwool, probably 90 percent even if the seedlings are not six inches tall, but the germination rate is 25 percent or less, except for a couple of varieties which is 50 percent.

So I'm wondering if Rapid Rooter plugs may be better. And if they are, should I also use a RR tray or just the plugs.

Your experiences?

Mike
 
Ok, by no means am I even close to knowing what I'm doing but I did germinate all my seeds using the Rapid Rooters and had great results. I transplanted the RR's in ProMix and the other in a GenHydro setup. I used the 72 seed tray and the RR fits snug right into them. I used the Hydrofarm Germination Station, poured a 1/4 inch of water in the tray, threw the top on and it kept the plugs moist. So far so good on all.
 
I have been trying the rockwool, and as a novice only have gotten about 40% germ. Soil, I was in the 80% range. I probably nanny my seedlings too much. The rockwool I can get at 96 plug sheet for $9.99 when I visit my brother in Orlando. The rapid rooter- the cheapest I have found is about 2x that. I may just go to try starting in perlite.
 
Rockwool is a very "flexible" material to work with, you just need to know how. works great for me.
 
treeman,

Does it make a difference using the tray vs. just the plugs? I have 10"x20" nursery trays, with and without holes in the bottom. It's obviously much cheaper to just buy the plugs.

Mike
 
Mike, are you conditioning the rockwool first? I soak overnight w/ a little citric acid, and water through some weak nutrients before planting. If you take care of that it's as good as anything else and holds an amazing amount of moisture.
 
I plant my seeds into small rockwool cubes, soak them in high-mineral water and switch to normal tap-water once they germinate. soon as my plants grow their first set of leaves I feed them a 1/4 strength hydro solution I mix. they grow fast and beautifully. because of my top-grade seeds I harvest and select, I usually get 100% germination.

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Zander,

I've tried soaking them first, both in tap water and water that has a pH of 7, using rainwater to keep them moist, using diluted hydro nuits. I get some success but 50 percent would be about tops except for one variety of toms that was 100 percent. But in the same sowing, the rate was about 25 percent. Even when the 100 percent germinated, they took about eight days to start and two weeks before four of the five were up.

I'm wondering if using the ones with the pre-drilled holes makes a difference?

Omri, glad to see you posting again! I can't harvest my own seeds - most of the plants I have never grown before. I'm trying different types of tomatoes to see which work best in an indoor hydro grow. Most are hybrids anyway, so seed saving is not advisable. The list that I will start in about 15 days:
BHN 589
IT 06 313 (now, AKA Pamella)
First Prize
Bush Goliath
Fantom Hybrid
Jetsetter Hybrid
Cabernet

I need to get six decent seedlings of each to grow.

Mike
 
Neither pH 7 water or tap water will bring down the pH to the recommended 5.5-6. The nutes may bring it down a bit, but a stronger acid might be just what you need. Still, I'm not completely sure that that would hinder germination as much as it would hurt during the active growing stage. I don't think the holes matter; I make my own smaller hole with a toothpick because it holds the seeds/cuttings better. Rapid Rooters are easier to the the hang of, but rockwool is pretty great once you've got it working.
 
The first (and only) rockwool cubes I did a few weeks ago I soaked overnight in pH 6.5 and only got one out of six to germinate....
but that could be because I had them in one of those mini germination greenhouses under a skylight on a very hot day and the ventilation holes were closed.

They got cooked :mouthonfire:

I'm going to try again tonight with precisely controlled under tray heating set at 29C which is 85F I think.
 
I sowed my seeds Tuesday evening and the first ones were starting to emerge this morning. That's as good as I get with potting mix!

Mike
 
Datil,

Tobacco farmers started using those Speedling trays several years ago, though they tend to use potting mix. I've had a chance to transplant some of the seedlings and I am impressed, to understate my feelings! Normally, the transplants suffer two days of setback until they start "digging into" the new soil - not these things. Don't wilt in the least and the transplant success rate is close to 100 percent. They are more expensive than growing in a bed or potting mix, but given that losing three plants out of 100 transplants can cost a loss of $50 in produce, or cost at least $5 in time and effort to replant, plus delay the plants by another week, it wis worth it. Plus, I can easily grow 1200 plants in the same area I can fit 360 growing in 3" nursery sells.

Mike
 
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