Article 4-1 Leaves Turn Upward

g’day guys. I have a urgent problem, i am growing from a strain and they are about 25cm tall, and four sets of branches out. the problem is cupping of the leaves towards the end of the day, slow growth, and not drinking much.

They are seedlings not clones. My running conditions are: feed, 1500ppm, being water 360ppm, nutrients 1140ppm,=1500ppm, ph=5.5-6.5, air temp=26°c,morn-34°c,night just before turn off when cupping is at its worst. tank temp=26°-30°c, they are looking ok in morn, but as day goes on they start to cup upwards from the sides of the leaves almost like the closing of a book. everything else seems ok (ie) greenness, robust, normal leafs, etc, would hope to get a reply a,s,a,p. all the best. yours sincerely, thanks .

Thanks for the email. Firstly, it sounds like you are dealing with water high in calcium and magnesium carbonate and possibly sulfur (“hard water”). If the fertilizer you are using attempts to supply these element assuming they are not present to begin with, you can reach excess levels. When this occurs, nutrients such as phosphorous can become unavailable. You can use commercial fertilizers such as General Hydroponics 3 part nutrients, with their “hard water micro” formulation. You can also get a water test to determine how much of the above mentioned elements are supplied by your water and create a nutrient solution around those quantities. Or try the following Hardwater bloom nutrient formula:

per U.S. Gallon (3.785 L) water

  • 2 grams Monopotassium Phosphate (0-52-34)
  • 2 grams Potassium Nitrate (Salt Peter)
  • 2 grams per 10 gallons Chelated Trace Element Blend

*Adjust strength to 1200 ppm or as required.

The above should work, and with some adjustments may prove to work well for you.

Your overall nutrient strength is too high for the temperatures you describe. Flush the system with plenty of fresh water. Use distilled water if possible. Try running your nutrient solution at quarter to half of your current overall strength. You can coil stainless steel tubing and place it in the reservoir. Cold water is then circulated through the coils, allowing more oxygen to be held in the water (dissolved oxygen) for healthier root systems. Pythium can be problematic in the conditions you describe. Inline U.V sterilizers can help prevent Pythium from developing.

You may have developed “soft” growth from the excess of high soluble nitrogen and high temperatures. Plants are then more susceptible to disease. Potassium Silicate can help to strengthen cell walls and protect against draught, but will typically decrease the % dry matter, as it tend to retain moisture within plant material.

If I was going to set up a large hydro system, what system would be the best to use? How can I contact a distributor? Who is the manufacture of the system? Would an NFT system be the most productive and lucrative system? Is there anyone I can contact for literature? PS: I’m looking for the best most cutting edge available equipment.

It sounds like you want the “Ferrari” of hydro systems. Most high-performance systems are temperamental and require a respectable level of understanding. However, well written instructions and feed charts can introduce less experienced growers to incredible results. Large scale systems are available commercially, or can be constructed from well sourced materials. There are many advertisements from reputable companies in Maximum Yield, visit one of their websites or request information to a mailing address. With regards to particular systems you may consider the following: N.F.T. systems can be very productive. Most tend to be manufactured for plants with smaller root systems. For larger plants, increased air space around the roots for gas exchange is preferred. With larger root systems and longer channels, nutrient gradients and decreased dissolved oxygen levels at plant sites further from the point of solution injection may occur. Plants producing significant mass will require additional support. Be careful of high root temperatures. Water based systems utilizing larger volumes of faster moving nutrient solution with several points of injection can overcome some of the draw backs associated with earlier N.F.T. systems. Rockwool with drip irrigation or the more simplistic flood and drains systems can be very productive. Growing in rockwool usually requires some experience or research for impressive results.

For plants taller than 3′ in finishing height and widely spaced, a bucket system is very well suited. It can easily be constructed using opaque 5 gallon poly buckets with lids and is less temperamental to operate. Look for systems that are founded on tried and true principles of hydroponic plant production to ensure results and try not to be in a rush if you can help it. When in doubt with your new system consider contacting the manufacturer or drop me a line!