Feeding Schedule for Baby Herbs

by Craig
(Seabeck, Wa. State; USA)

Years ago I had the art of growing by hydroponics down, somewhat, and was reasonably comfortable with it. I'm now deciding to try it again with super stock after a ten year period of dormancy. One thing I'd like to know is: What is the optimum nutrient watering schedule? I mean how often, for how long, and with how long in between allowing for drying before re-irrigation of feeding?? Is this night and day? The plants right now are two weeks old and are about three inches high on average (and seem reasonably healthy). I'm putting them into my Jetstream 6-tray system now and just don't remember what their feeding schedule time-wise is all about... Please help me!
Craig

Answer: Craig- whenever using rockwool, make sure to first pre-soak the rockwool in pH adjusted water before you put your plants in. Rockwool has a naturally alkaline pH that will mess with nutrient availability. Pre-soaking will also help the nutrient solution get into corners of the rockwool where they would not have made it before if you start with bone dry rockwool. Your plants constantly take up water and nutrients to grow (even during the night). Without a steady exchange of fresh water and nutrients around the roots, you may end up with a pH problem or a low oxygen problem. My advice is to irrigate your medium both day and night.

Rockwool absorbs water quickly, and tends to hold onto a LOT of water. This means you can irrigate it with less nutrient solution than other mediums (expanded clay pellets, for example). For a drip system, the proper rate of irrigation would be about 1 drop per second. This should equal one or two gallons per hour. With a drip system the irrigation is constant....there is no "watering period/drying period" cycle.

For lettuce and baby herbs, such as oregano, sage, basil, cilantro, mint, etc.....a 50% strength nutrient solution should work very well start to finish. For most hydroponic nutrients, this comes out to 600 or 700 parts per million (ppm) on a TDS meter. Heavier feeding garden plants (such as tomatoes) can be started 700 ppm as babies, but should be increased by 100 ppm every nutrient change (through veg AND flowering) until you begin to notice the slightest burning at the very tips of the leaves. This is known as the "perfect greenhouse burn" and indicates the maximum strength nutrient solution you should use on your plants. For heavy feeding plants, this is usually around 900-1200 ppm.

Keep in mind, ppm reading will vary a little from one TDS meter to the next. It is better to err on the side of low nutrient solution strength and work your way up rather than burn and kill all your plants. Hope this helps, and Happy Growing!