I am fairly new to hydroponic growing. I was very disappointed in my first crop. The yield was way below expectations. One of the problems I had was the leaves turning brown and curling up. I thought that they were too close to the light, but round two is starting to show signs of same. HELP, do you have any suggestions. I would love to hear them. Thanks guys.
Sounds like a possible salt build up in the growing medium. If you are growing in a non-recirculating system, make sure there is at least 10% run-off with each irrigation cycle. Also, if non-recirculating, fertilize at full strength every third irrigation or with 1/4 strength fertilizer at each irrigation.
Addition of dolomite lime in peat mixes helps to buffer nutrient toxicity and will slow release plant available calcium and magnesium If you are growing in a recirculating system, flush the growing medium with lots of fresh water once a week before adding new nutrient solution.
The description you have given suggests a magnesium deficiency. For a quick remedy you can apply a foliar spray with about 1-1/2-2 teaspoons per litre of U.S.P grade Epsom Salts (magnesium sulphate) which can be purchased inexpensively at your local drugstore. It can also be used to supplement your nutrient solution or incorporated into soilless mixes such as peat and coconut fiber. About 500 ppm of Epsom Salts will yield approximately 50 ppm (optimum) of magnesium in the nutrient solution. As mentioned above, fine and coarse dolomite lime mixed into soilless mixes will provide slow release calcium and magnesium, buffer pH, and reduce nutrient toxicity. Five cups per bale of commercially prepared mix should do wonders.
Make sure to check the pH of the nutrient solution and compare it with the pH of the growing medium. Keep at it, and I think the above suggestions will help.
Thanks for the email.