Questions

• I have some very pale looking lettuce sprouts!
• Help! My plants are dying!
• My plants have a brown stem and brown roots.
• I have a spider mite problem.

Answers

I have a spider mite problem. I use safer soap and an automatic Magic Mist sprayer and still have a problem. I need an agressive spray to get rid of them. Can you help me out?

ARGH!! Spider mites. Unfortunately, anything that would kill the eggs is a systemic which would harm you when the end product is consumed. We must use 'safe' products. The best way to combat spider mites is with the host specific predator 'persimilus'. They are twice as fast as the spider mite and reproduce twice as fast.

The trick with these pests is to kill the adult before it has time to lay more eggs. I am assuming these are stock/mother plants and not flowering plants. Spray every 3rd day to stop the adult/larval/egg cycle. This means for example to spray monday, wednesday, friday, sunday, tuesday, thursday, saturday, monday etc. for at least two weeks. Make sure you spray under the leaves where they are hiding, manually pick off any adult or webs you see before spraying. Use Virkon on the rest of room as an added measure.

I have some very pale looking lettuce sprouts!

The pale look is due to lack of nutrient. Start feeding with a hydroponic nutrient immediately. Start with half strength and increase slowly to full strength over the next week or two. You may foliar feed (spray the leaves) with a dilute strength solution (about 1/3 strength) to help them green up faster.

 

Help! My plants are dying! Quick summary: 13 square feet of two ebb and flow trays with a 1000 watt HPS. The plants had a 400 watt MH, but I decided to give them more light, because they are about 6 weeks old. I have had a real problem with how concentrated a solution I should use.
They are in rockwool with slabs. Some of the plants are tall and green, while others have beautiful green tops, but soon turn yellow with leaves that either have tips that curl up or the whole leaf droops.

Consequently, the leaves die. The temp is 89 with CO² supplementation and circulation. I water twice daily. I use a 7-7-7 solution with all micros in the same bottle. I have used as high as half strength to as little as 25%. My water is from an osmosis machine, so it is pure. What is a good strength to use? My solution has everything, but new growth has burnt tips on the leaves. I know I am rambling, so my prayers are for a response.

Your plants have a few deficiencies, magnesium is one of them.

You need to get a proper Hydroponic nutrient and use it full strength. The 7-7-7 will never be good nutrition for your plants.

Your temperature is also much too high, even with CO2 enrichment, vent with a blower fan and circulate with an oscillating fan.
The 1000 watt MH is creating a lot of heat for this small area, the plants also require more nutrition with higher light levels. Change back to your 400 watt or increase you growing area.

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Jack's Info on Hydroponic Plants and Light

We are growing basil using a fill and drain method and our plants seem to turn brown up the stem and then topel over and die when i take the dead plants out the root system is abundent but the roots are brown also.

Your plants may have a fungus called 'Damping Off', are they turning mushy where the stem meets the growing medium? Damp Off is usually a problem when the humidity is too high. Damp off attacks seedlings and younger plants first and spreads to larger/older plants. It is easily countered using a fungicide such as 'No Damp'.