Tomatoe nutrient problems?

[joe.jr317]

I know this is kind of old, but for anyone just looking here for the first time. . .

I've learned through trial and error, research, and a friend that worked with Purdue University in Ag that calcium is rarely lacking so much as the plants ability to use it is. The most common causes are supposedly hot reservoir temperatures which affects the water's ability to hold oxygen and too high of EC which inhibits hydration. Calcium doesn't move without the water and it has to be constant since calcium is not mobile. Once it's in place the plant can't recruit it in reserve. Low oxygen also means low uptake. Can't recall the technical explanation, so if someone knows then please jump in.

Now, I'm not an expert and what I wrote there may not be completely accurate. I didn't write the stuff down like I should have. Just remembered the fix. See, the reason I did so much research was because I was having serious issues with deficiency. My tomatoes were in waterfarm type systems and the buckets were exposed to direct light outside. Plus, behind them was a white wall. The water temps always stayed high. Consequently, the CalMag I kept putting in did no good. I was at a loss. Now I realize that it didn't matter how much CalMag I used, the plants simply wouldn't have ever been able to take the stuff up. I cooled the reservoirs by shading with insulation left over from putting up siding. Guess what, the blossom end rot went away. . . The tomatoes were San Marzano Romas, by the way.

[GpsFrontier]

I've learned through trial and error, research, and a friend that worked with Purdue University in Ag that calcium is rarely lacking so much as the plants ability to use it is. The most common causes are supposedly hot reservoir temperatures which affects the water's ability to hold oxygen and too high of EC which inhibits hydration. Calcium doesn't move without the water and it has to be constant since calcium is not mobile. Once it's in place the plant can't recruit it in reserve. Low oxygen also means low uptake. Can't recall the technical explanation, so if someone knows then please jump in.

Do you recall the optimum temperatures for calcium uptake? I try to keep my reservoir temperatures between 68-72 degrees, that doesn't mean they are all the time but that's what I aim for. That's what I understand to be optimum temperature for the root systems of the plants, and constancy is important. I am not sure how the uptake is affected by oxygenation (I am no expert), but that makes scene. I've learned about the importance of the right nutrient temperature myself last summer, specifically because of my strawberry, and pepper plants.

P.S. Do I understand correctly that too high of a concentration of nutrients in the nutrient solution also inhibit hydration? I know that in warm weather they don't need as strong of a nutrient solution because they transpire (evaporate) much more water. I was thinking that this is because the nutrients become much more concentrated as the water is used up faster.

[joe.jr317]

1) Yes, high EC reduces the uptake of water. Actually, it reverses it when bad enough. If the EC of the solution is higher than that of the root, water will be drawn out. I got that from "Gardening Indoors with Soil and Hydroponics," by George F. Van Patten. Page 168. Also, this is why it is important to occasionally flush your medium for optimal growth. Salts build up in the medium making the EC too high and leading to dehydration even if your solution seems fine.

2) I don't recall the optimum temps for calcium, but was advised to shoot for 70-75F in general and I'd be "golden". I'm back in school now for biotech, so I will be sure to share anything relevant that I learn.

[GpsFrontier]

Yes, high EC reduces the uptake of water. Actually, it reverses it when bad enough. If the EC of the solution is higher than that of the root, water will be drawn out. I got that from "Gardening Indoors with Soil and Hydroponics," by George F. Van Patten. Page 168. Also, this is why it is important to occasionally flush your medium for optimal growth. Salts build up in the medium making the EC too high and leading to dehydration even if your solution seems fine.

This is good to know, I don't have a EC/TDS or PPM meter, but I mix my nutrients according to the directions, and now I am starting to mix them weaker. My problem is that sometimes I don't keep up with replacing the water that the plants have drunken up. That leaves a concentrated nutrient solution to what water is left. I was adding 3 gallons of fresh water to my tomato plants every day, then after about 5-6 days I wanted to check the pH, so I pulled the lids up only to find there was only about 5 gallons of water in what was a 15 gallon reservoir. So I know that the water that was left was highly concentrated.

I also flush all my systems with fresh water in between every nutrient change to flush out the old nutes and salts. I don't have any more FloraKleen so I just use fresh water, then dump that before adding the new nutrient solution, and occasionally I flush it more than once.

P.S. that sounds like a good book I'll look into it. I also want this book "Hydroponic Strawberry production" by Dr. Lynette Morgan. But none of the library's have/or can get it, including the collage. Unfortunately all I can do is buy it and it runs about $60, that's a bit steep for me right now.

[joe.jr317]

If I remember right, you mentioned using the Flora series. I have found the EC to be pretty high if I follow the instructions on those nutes, so I often reduce it by about 25% and even more in the heat of summer. I use rain water, so I start with an EC of 0.

If there is anything you want me to look up in that book, I'm more than happy. I use it as a reference all the time. I'm using it as a textbook for my son, whose learning hydro, too. He's 13. My 9 year old will be next.

Yeah, $60 is steep. Of course, strawberries aren't cheap and they're really good for you, so it might pay for itself quickly if you happen to run into some extra cash. I like strawberries, but my wife really eats 'em up.

[GpsFrontier]

Ya I am using the Flors series, although recently I am testing another type from Vertigro that was given to me. I probably have been mixing my nutes a little strong at about 10mL per gallon of each, that was what GH had recommended for most of my plants (peppers, strawberry's and tomato's). I only have tomato's going right now and a makeshift drip system for some melons that I hope to transplant soon. The nutes for the melons are the virtigro nutes. The tomatos, I recently reduced the strength. I mixed as normal (10mL per gallon) for 10 gallons, but then I added an extra 5 gallons of straight water. I have no idea what the EC/TDS or PPM of my water starts out with, but I use Reserves Osmosis water, sometimes I add about 10% hard water from outside (after boiling to get rid of any pathogens).

I am planing a hydroponics farming operation, and my first main crop/s will be strawberry's and peppers. Not real large but it's planed for about 640-700 strawberry plants and about 40 pepper plants. I have already designed the system for the strawberry's that mimic's the system on the front cover of the book by by Dr. Lynette Morgan. Although I only recently found out that picture was from that book. Now I want to get all the details that I can strait from the horses mouth (so to speak). I love strawberry's and plan to make it a year round operation. We don't have any local farms here for strawberry's, not to mention year round berry's. I have even discovered that when I want/need to expand, a local nursery here on the north side of town is willing to let me set up shop there. He has getting into selling hydroponic nutrients (the only one in town) and has 9 acres of land, he said we could work something out.