Tomato Lower Leaves Yellowing

[Izzie1701]

I am having some troubles with my hydroponic tomatoes. This is my first time growing. My bottom leaves are turning yellow and don't look healthy. I have planted all my tomatoes from seeds. The plants I planted in the ground are growing twice as fast as the plants hydroponically and look a lot healthier. From everything I have read it appeared I had a lack of nutrients. I purchased a TDS meter yesterday and tested the water. It was at 2200ppm. I thought this may have been high and was due for a nutrient change so swamped the nutrient out and adjusted to 1300ppm as it indicated it should be at on the nutrient bottle. I am using a 2 part nutrient with a third boost nutrient. From further readings it looks like tomatoes should be fine with a nutrient level of 2200ppm. I am running a dwc system. I have my tomatoes in rockwool surrounded by clay pellets. I have about 1" of the bottom of the rockwool sitting in the water as the roots are yet to protrude through the rockwool and dangle into the water. I have a 6" air stone in a 5 gallon bucket supplied by an aquarium pump for aquariums up to 80 gallons. I would hope this is enough air. Any idea on what the issues could be. The leaves are just yellow no droop or curl up.

[evtubbergh]

I opened your post because I often have yellowing tomato leaves and then saw it was about hydroponics. I don't know if it would make a difference but mine go yellow from lack of sun and from fungus that splashes up from the soil. I'm guessing the latter is not an issue but what about the former?

[rainbowgardener]

Yes, you didn't say anything about the lighting. I don't know much about hydro, but I think it is typically done indoors. If so the lighting is crucial. Getting a tomato plant to thrive and set fruit requires lots of light. One of the causes of yellowing leaves in outdoor tomato plants is that they are not getting enough sunlight.

That said, it doesn't surprise me in the least that the plants in the ground are growing better. It is what they are adapted for. In the ground are an array of micro and trace nutrients and minerals that your hydro system can't provide and a whole community of micro-organisms that function to turn all the nutrients into forms the plants can best use and transport them into the roots. If you have ground space to plant things, I don't know why you would want to do the hydro.

[applestar]

This is just a guess on my part as well. (We need the hydro folks here to answer this question. )

I have my tomatoes in rockwool surrounded by clay pellets. I have about 1" of the bottom of the rockwool sitting in the water as the roots are yet to protrude through the rockwool and dangle into the water.

I'm thinking what you want to do is have the water barely lapping the bottom of the rock wool and not soaking in it? I'm thinking you just need sufficient moisture to keep from complete dehydration and the plant WILL seek out the water and grow the roots down.

Also, what are the specs for this air pump that is supposed to be good for 80 gallons? For my AACT, I started out with 1000 -- totally inadequate -- then upped to 2000 and now, I'm using the 3000. Almost no such thing as too much air pressure it seems.... The stone clogs very easily especially in presence of nutrients. I have to soak in peroxide to clean every so often (can't remember exact span of time before needing to clean).