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2/27/2003 2:41:00 PM
black slime

I got this black slime or tar colored stuff in my rockwool. Is it dead algea or mould?
How do I get rid of it.
Also I have my plants in a 6inch rockwool cube, roots have fully taken over the cube, but there all very small,there is on one plant with a large branching root(fish bone pattern root)but in general all of the roots are small and of the small ones the tips that are protruding out is brown colored instead od white.
The plant's are alittle over two feet tall, and started from cutting.
Is there a probblem with my root system as far as size and what can I do to fix the probblem?
How do I fix the browning tips of the roots?
The Green Thumbs
2/27/2003 9:20:00 PM
Re: black slime

Chances are pretty good that the black stuff is a form of algae. If the texture really is "slimy", then I would bet on it. Algae is quite common, and shouldn't be too much of a problem unless it really starts to take over your reservoir. You are using hydroponics, and not soil correct? (Algae is most common with hydroponics)

As far as your roots are concerned, if the plants are doing fine, then you shouldn't worry too much about the size of the root mass. If there is something wrong with your roots, the plant would definitely show it. What kind of fertilizer are you using?

Brown root tips aren't necessarily good, nor bad. Plants will still do just fine with brownish roots. If the plant had near-perfect environment conditions, the roots would probably be white. How often are you changing your reservoir? Are the plants indoor or outdoor? If they are indoor, how much light do they get, and for how long?
2/28/2003 1:18:00 PM
Re: black slime

well I'm doing hydo, in door , with a 400 for veg, and using botoniccare power plant,in a ebb&flow. 18/6 is my current light setting with a temp of 75 to 77.
Humidity is very low in the room,like low 20's.
I'm changing the res. every two weeks.
My plants are bushy and green but vertical growth has stopped is there a good reason for stunted grow, can it be fixed.
Btw, condition were not away so pleasant, I used to use a 1000watter but couldn't control the heat and dropped to a 400.
The Green Thumbs
2/28/2003 11:39:00 PM
Re: black slime

What type of light do you have the plants under: Metal Halide, or High Pressure Sodium? Metal Halide (fat pear shaped bulbs) lights primarily emit the part of the light spectrum that promotes growth, the white/blue end. High Pressure Sodium (long thin bulbs) bulbs emit the flowering end of the spectrum, the red/orange. If you use the HPS light throughout the whole plant cycle, you will most likely see a stunted growth pattern, as the plant may not be receiving enough growth stimulating white/blue light. The most common occurances of using only an HPS bulb is to have short, stocky plants that should produce typical flowering/fruit yield for the height of the plant. If you were to use only a MH bulb, you would see your plants become tall, thin, and not produce a typical yield.

Here are my 2 suggestions that could help you out:
1)Keep an MH bulb on the plants, until they hit the flowering cycle. Once the flowering cycle begins, switch over to an HPS bulb. This will help the plant grow to its full potential.
2)While the plant is in its growth stage (with the MH bulb), you should be feeding the plant a fertilizer that is high in Nitrogen. Nitrogen promotes the growth in the plant. Once the plant switches over to the flowering stage, you should switch fertilizers over to a formula high in Phosphorus. This promotes flowering. I hope this helps you out.
3/1/2003 3:20:00 AM
Re: black slime

I do use a MH for my veg. a 400 wat one now.
I use to use a 1000 MH, but could'nt control the heat, so I dropped down to 400, been on the 400 for a month now, but my clones just dont seem to be getting any taller.
But since I have you on the subject of light, what are the benifits of using a combination of MH & HPS through out the life cycle of the plant?
I'm seeing a lot of these " full spectrum lighting systems " both HPS & MH in one reflector.
Does your veggie come out better tasting & fuller. Or is it just a marketing hype?
The Green Thumbs
3/1/2003 9:08:00 AM
Re: black slime

Honestly, if you want the best results you can get out of your plants, then using a full spectrum lighting system is the way to go. For example, probably the most popular one is <a href = "" target = "_blank">Sunlight Supply's Super Spectrum</a> system. It contains one MH bulb, and one HPS bulb, under one hood. This is the closest you will get to natural sunlight. Anytime you can provide both of the spectrums from MH and HPS, you definitely see a lot better results in both your growth stage, and your flowering stage. It is definitely not marketing hype.
7/2/2005 4:36:42 PM
Re: black slime

you should be able to just scrape off the black slime(algea)and cover the rockwool with paper or something, to keep light from getting to it..
the algea seems to needs light and water to survive, you need to have water on the cubes but not light...i hade i slight problem with algea in my soilless mix..but now the plants have filled out nice and not much light can penetrate through...
Willard Bridgham 3
7/3/2005 9:29:34 AM
Re: black slime

Have you had your water tested for slime mold?

All municipal water system piping has slime mold that chlorine will not remove. Slime mold makes a black deposit.

Treating all water w/500 ppm H2O2 (1 tablespoon/gal) will control slime mold.

Could also be algae and control of light on nutrient is the only way to control it.
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