Your fertilizer is definitely designed for hydroponics systems, though I've never used it. I originally used a one part fertilizer that was pretty similar to yours, (3-2-5) and it worked fine in my inexperienced eyes, except the vegetables I grew were very leggy, which I blamed on the HPS light.

Did the person who helped you offer a reason why he thought you should go with crushed shale vs. expanded clay?

Yes, he said since it is heaver and denser than clay pellets it would support a taller plant better. I am planning to grow a tomato plant with hot pepper plants. He showed me some plants moving in clay pellets and others in the shale. It appeared to make sense but IÂm not sure if itÂs the best medium for a bubble bucket system, thus my original question.

I have had great success with PBP and would suggest it to anyone. It's very easy to use and harder to burn your plants with vs a chemical fert. Give it a shot. I start out with 1/4 to 1/2 the strength suggested on the bottle and go up from there.

Thanks for the feedback folks.

I decided that the shale was going to me too heavy to work with given the small rim on the baskets IÂm using. Although I didnÂt try it I figured the basked would probably fall through the holes I cut into the lid of my bin due to the weight. Returned the shale and picked up a few bags of Perlite at a local hardware store that had them it sale for $2.39 / 5 liter bag.

I have my first bin done, six 3.5" mesh pots with wicks. I have two 8" air stones / sticks hooked up to a pump. The bin has 11 gallons of 50% strength of Pure Blend Pro and my first readings on the mix are pH 6.4 and EC 832 ppm.

Does this sound right? IÂm planning on growing lettuce and spinach in this bin. IÂm going to try to germinate the seeds directly in the Perlite. IÂll let you all know how I progress.

Bill

I know I'm going off on a tangent here but I would argue that the growing medium for tomatos does not provide the majority of the support for the plant. Unless you are growing a dwarf determinate variety (such as Totem) the vine will need some form of external support just as they do in a soil based garden.

Back on topic-

I don't think it will make a huge difference. I like expanded clay for E&F systems because the porosity holds more moisture during the flow cycle to keep the roots from drying out. In DWC, if your roots dry out you have bigger problems than your choice of growing media. I think your growing media and nutrient sound fine. We want pictures of the system when you get it up and running.

-backwards

832 PPM sounds a tad high, especially for germinating. I would germinate them in a tray... inside a rockwool cube or jiffy pellet etc, then put them in your system after they get their first set of real leaves and some roots. Germinate with plain tap water, no nutes. I'd start off with a PPM of about 100 to 200 above what your tap water is normally. In my experience, I have never been able to run the nutrient concentrations suggested on various bottles and web pages. I have read and attribute that to the DWC design. The most I've ever gone was around 400-500ppm during full-on mature plant growth in flower. Any more than that and they'd lock-out which would set me back weeks. In my experience, start out with less nutes, then slowly build up, only when you see that they could use more (yellowing of lower leaves etc).

Getting the nutrient strength right is the hardest part of hydro growing in my opinion because you need different strengths for different plants and for different systems. 400ppm in flood and drain is different from 400pm in DWC which is different from 400ppm in an aero system etc.

Thank you hind sight,

This is information I can use... been trying to figure out where my nutrients should be. I think I have a handle on pH but have read that you can kill with kindness when it comes to nutrients in hydro systems.

Bill