Spots on pepper

[StrangGuy]

Hi,
I would like to thank the members of this forum because I have gained valuable information from here. I am a first time hydro grower with a brand new home made unit. It is constructed of 4” PVC with 3” net cups and has sprayers that perform at 180 degrees on each side of every cup. I use LECA (Lightweight Expanded Clay Aggregate) as the support medium and 20 gallons of Liquid Earth as my nutrient solution. My PH is 6.5 and I do not have a PPM meter. The system is currently located outdoors around Atlanta, GA.
I germinated bell pepper plants from May 30th so they are about 3 weeks old. I used Perfect Start #2 which I thought to be great as all but one was germinated. I currently have 62 plants total and will only use the strongest 48 as they mature.
So, I have the system ready to transplant my plants into and here starts the problem. I didn’t use a separator in my seeding tray so almost all of them had roots growing together. So in pulling them apart it was like pulling open a treaded stitch at times. The roots still really looked good for the most part and the plant looked healthy at that moment so I added them all to the system on the evening of May 20th (two days ago). Yesterday they were all fell over but today they are all perky and standing up. We have received a few thunder storms as well on them.
One other thing that may be of importance is that my nutrient mixture has changed. I followed the mix instructions on the bottles to make one gallon of “Mild, for seedlings and cuttings” which was 1tsp Grow and 1tsp Vigor. I used that gallon up to the point I was ready to place into the hydro system. However, when I made my 20 gallon batch on Thursday, I followed the manufactures spec sheet for young peppers in which the 1 gallon equivalent would have been 0.4tsp Grow and 1.4tsp Vigor. So, that is a lot different.

If that is not enough background then please ask for more specifics. Please respond if you can assist with the answer to any of the following.

Question 1: In the attached pictures you can see that I have some spots on a few of my plants. 6 plants to be exact with is about 10% and the pictures are the worst 3. I don’t think that I have bugs so I am wondering could it be a consequence of tearing the roots or to I have some other problem?

Question 2: Can plants be too wet with nutrients? I have had the system on continuous since I started on Thursday night. I never kept the Perfect Starts that wet during the germination stage as they are like a sponge. I have a 15/15 timer. I think that a setting of 15 on and 45 off should be good to keep them nice and moist.

Question 3: Out of the 20 gallons of nutrients that I started with I am now down about what appears to be 3-5 gallons in just 2 days. Can I add 5 gallons of water and nutrient amount for 5 gallons?

Thanks,
StrangGuy



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[GpsFrontier]

Question 1: In the attached pictures you can see that I have some spots on a few of my plants. 6 plants to be exact with is about 10% and the pictures are the worst 3. I don’t think that I have bugs so I am wondering could it be a consequence of tearing the roots or to I have some other problem?

I doubt that tearing the roots has anything to do with the spots, plants can normal take that sort of thing without any problems. If you do tear too much they just normally look wilted until they can grow enough roots back to uptake enough water to support the plant.

Question 2: Can plants be too wet with nutrients? I have had the system on continuous since I started on Thursday night. I never kept the Perfect Starts that wet during the germination stage as they are like a sponge. I have a 15/15 timer. I think that a setting of 15 on and 45 off should be good to keep them nice and moist.

If I understand correctly the system has been running for continuously for around 36 hours straight, I don't think this would cause the spots but will become a problem if you don't cut it back. You have a 15 min timer, I would start it at 30 on 30 off at first. As the plants get a little bigger, or maybe in about a week try 15 on 45 off, and if you see any signs of wilting step it back up. Of coarse a lot depends on your local weather, if it's cold and/or damp 15 on and 45 off may be fine to start with, just check for signs of wilting.

Question 3: Out of the 20 gallons of nutrients that I started with I am now down about what appears to be 3-5 gallons in just 2 days. Can I add 5 gallons of water and nutrient amount for 5 gallons?

Here is where I think your problem starts, If I understand correctly you have 62 plants feeding on the one 20 gallon reservoir, I don't know how much solution is left in the system when it is shut off. But the plants will drink up the water, small plants not nearly as much as larger plants but you have quite a lot of plants that are using it. As the plants drink up the water they take up the nutrients also, but only what they need and leave the rest. Then as the water level in the reservoir drops, the leftover nutrients become concentrated. Then you go from 20 gallons down to 3.5 gallons, that's like putting 20 gallons of nutrients into 3.5 gallons of water, it becomes a highly concentrated nutrient solution.

First off you are going to need a MUCH larger reservoir. Another member had asked about what size reservoir they should use for 40 pepper plants about a week ago in this thread: http://www.hydroponicsonline.com/for...-question.html, I recommended at least a 400-500 gallon reservoir, as well as a fresh water replenishment system. You plan 8 more plants than that. Each plant will use between 1-2 gallons of water daily, 2 gallons when they become full grown maybe even more if it is real hot. Doing the math that is 2x48= at least 96 gallons of water that needs to be replaced daily. Fluctuation in the nutrient concentration wont do your plants well, and likely have many plant problems.

Even with a water replenishment system in place to keep the water level consent you can have fluctuations in nutrient concentration of the individual elements in it. As I mentioned before the plants will take what nutrients they need and leave the rest, the nutrients they take up will become depleted, and the ones they leave behind will become concentrated over time and become imbalanced. So the larger the reservoir the more buffer water you have to guard agents fluctuation and imbalances, and help provide a consistent nutrient solution.

[StrangGuy]

Thanks GpsFrontier!
I’m sure that you are accurate with needing a larger reservoir and I plan to take this advice and increase the size. What I do find strange is that up to this point I was able to feed them for 3 weeks on less than a gallon of nutrient/water solution but once in hydro system they are requiring that much more so immediately. I also wander if evaporation is playing a big part here.
My follow up question is, what can I do at this point to make them happy/spot free prior to adding larger reservoir? Obviously I need to add water, but how do I know how much nutrients to add with that water? It states that my PPM should be 472 at this young vegetative stage. Should I next day a PPM meter and add nutrients until I reach this level?
Thanks again for your help!

StrangGuy

[GpsFrontier]

I’m sure that you are accurate with needing a larger reservoir and I plan to take this advice and increase the size. What I do find strange is that up to this point I was able to feed them for 3 weeks on less than a gallon of nutrient/water solution but once in hydro system they are requiring that much more so immediately. I also wander if evaporation is playing a big part here.

Evaporation (non plant transpiration evaporation) could defensively play a part. I don't know how ether system is really built, so I don't know where gaps in the system may be. Also I don't know how much they have grown sense you transplanted them. Also I don't really know from where you are measuring it. For instance, the growing medium will suck up (absorb) some, lets say each plants growing medium sucked up 1/4 cup, 1/4x62= 15.5 cups or about 1 gallon. A little here, a little there all adds up.

Also no mater how much you try to drain it all, some will be left in the system. With that many plants I can only gather it's not a small system, half a gallon left in 10 tubes, well that is five gallons. I assume you have checked for leaks. Once it's up and running and the system is topped off, I would check it every day at the same time. Then measure how much you need to add back daily, that should give you a good idea how much is being used, provided there is no leaks. I mark the inside of my reservoirs with a permanent marker so I know the exact level.

what can I do at this point to make them happy/spot free prior to adding larger reservoir? Obviously I need to add water, but how do I know how much nutrients to add with that water? It states that my PPM should be 472 at this young vegetative stage. Should I next day a PPM meter and add nutrients until I reach this level?

I cant guarantee that they will be spot free by replenishing the water and/or any nutrients. But I would fix the water fluctuation problem first in order to eliminate it from the list of suspects. I don't even have a PPM/TDS or EC meter myself, but for that size setup I would probably recommend one. Though I don't see any need to overnight anything at all. These meters just tell you how concentrated the solution is, they cant tell you what nutrients are actually in it, and in what concentrations each of them are in, it's just the total amount, including what was in the water in the first place. Kind of like saying I have $14.87 in my pocket, that doesn't tell you how many 10's, 5's, 1's, quarters, dimes, nickels and penny's I have. They could be all penny's.

But they can tell you how fast the nutrients are being absorbed, assuming you are testing it at the same water level every time. You don't need a meter to let you know that the nutrient solution is concentrated when you have less than 25% of the water left in a couple of days. I would not add any nutrients back if it has only been a couple of days, just fresh water. And check pH every day after replenishing the used water. I wouldn't even bother with PPM/TDS or EC at this point, with such a small reservoir it's likely to change hourly with that many plants.

Even by adding more nutrients back to bring it back up to a particular level, the elements that were not used by the plants will become concentrated, and possibly cause nutrient lockout, especially in such a small reservoir. It's much simpler and easier to change the small reservoir much more frequently. Possibly twice a week. That's 40 gallons of nutrient solution a week, and replenish the water daily, as well as checking pH daily. I use pH drops, but I would suggest a pH meter for you first (needing to check it so often), then a PPM/TDS or EC meter.

P.S. I would love to see pictures of your setup. Also the plants don't use up the nutrients in proportion to the amount of water, they simply take what they need and leave the rest. I wouldn't add any more nutrients at this point, as mentioned I would just change the reservoir more frequently. Just so you know I'm not an expert, I'm just a guy that tries to help others from my experiences when I can.

[StrangGuy]

Thanks! Some pictures per your request.





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[GpsFrontier]

Thanks for the pictures, it is a cool looking setup, but I do have a concern. I am unclear if this is a temporary system, or the final destination for the pepper plants. I am concerned because each plant (unless dwarf variety's) should get about 3-4 feet wide. The spacing looks to be only a few inches apart, that would be a huge problem unless it was just a starter setup for that many plants, and you intended to transplant them into another setup.