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'.