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Hey everyone,

I have some plants growing in my AP system and they just don't seem to be doing that well. After reading through some posts on here i decided that i should check some water quality characteristics besides the basic ammonia, nitrate, nitrite, pH stuff. I figured a nutrient deficiency could be best approximated with hardness and alkalinity, and sure enough they are both pretty low. So how do i correct this issue without raising my pH. Currently my pH is in the mid to high sixes, which is right were i am trying to keep it. I supplement water replenishment almost soley from rain collection. So my system is definitely lacking in nutrients. Everything that i see about adding nutrients usually is in conjunction with raising the pH. So it there a way to supplement nutrients without raising the pH or do i supplement and then correct pH.

Thanks

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Hi there sticky...before even attempting to address any nutrient issues, you should know that even in the most well seasoned, nutrient laden set-ups, things like peas and spinach (which you've pictured) probably aren't going to do well in places like Lady Lakes Florida. Those are generally cool weather crops that fail miserably in your mid 80's temperatures. And yes, many cool weather greens and lettuces get milky and bitter in the heat...particularly when any additional environmental stresses are added to the mix (low nutrients, high nutrients, things are too wet, things are too dry etc)...

Try to work with your seasons and your particular environment by growing seasonally appropriate crops. 

It very well may be that you have some nutrient issues as well...I don't know what else you're growing or what they look like, but the spinach and peas are probably;y a no-go for this time of year irregardless of plant essential element issues :)

Thanks for the input, the heat is definitely an issue. i lost a lot of plants and a lot of fish last year and the only reasonable thing it could have been was the heat. As it all started about the same time, August. I have a greenhouse that i am going to set up. For now i am leaving off the plastic covering and going to get some shade cloth to help with the longer, hotter days. the lettuce and spinach i actually planted back in February, i was trying to thread the needle of an early start without getting any freezes. i had planned on starting earlier but the winter just seem to keep going so i waited.

in terms of combating the heat, would keeping my water temp down be a worth while venture. i am going to set up insulation on my fish tanks this year so i don't loose fish to the heat. would maybe going a step further and icing the water be useful in protecting my plants from the heat. i have a dual tank set up, so i could add ice to my sump tank and not directly to my fish tank. 

 

Vlad Jovanovic said:

Hi there sticky...before even attempting to address any nutrient issues, you should know that even in the most well seasoned, nutrient laden set-ups, things like peas and spinach (which you've pictured) probably aren't going to do well in places like Lady Lakes Florida. Those are generally cool weather crops that fail miserably in your mid 80's temperatures. And yes, many cool weather greens and lettuces get milky and bitter in the heat...particularly when any additional environmental stresses are added to the mix (low nutrients, high nutrients, things are too wet, things are too dry etc)...

Try to work with your seasons and your particular environment by growing seasonally appropriate crops. 

It very well may be that you have some nutrient issues as well...I don't know what else you're growing or what they look like, but the spinach and peas are probably;y a no-go for this time of year irregardless of plant essential element issues :)

Bottom older leaves yellowing= nitrogen deficiency. Your nitrate and nitrite readings of 0 support that. You have a lot of fish....Are they eating? Are they teeny tiny? Why are nitrogen levels so low?

I use liquid iron. It's readily available. The one I have has lots of other trace minerals in it too. Without it, I could grow leafy greens but tomatoes were limited.

You'll have to experiment with portioning.

I hope this is useful.

FYI, There's a really great discussion on iron on this this thread.

Sea salt, or even plain old sea water, quite an array of trace minerals in it...and even some secondary elements like Mg (though often the companies who make solar salt, sea salt, pool salt strip out the Mg and other elements along with it, and sell those contents off to other industries...so be aware of that).

It's very interesting that you heaviest feeding plant, the sunflower, appears to be doing just fine. Spinach and peas (especially in a veg. phase) are total lightweights compared to the amount of plant essential elements it takes to grow a big 'ol sunflower plant. Isn't it curious that this heavy feeding plant is doing just dandy, while comparatively light feeders are suffering? 

The sunflower plant also happens to be a warm weather crop. The plants not doing so well are all young cold weather crops trying to grow in 80-90 degree temperatures which is very, very difficult for them. Their physiology just isn't built for that, regardless of the presence of sufficient plant essential elements. If any one can "figure out" which trace element will allow young spinach plants to thrive at high temps, you stand to become quite wealthy in the field of agronomics 

That said, their are many, many ways to supplement plant essential elements, (your choices as to what/how should largely depend on what it is that your system is lacking in)...My personal favorite supplement is free, readily available, is full of things like nitrogen, phosphorous, potassium, calcium, magnesium, iron, zinc, as well as many trace elements...and it doesn't take electricity to produce, or diesel fuel to ship it around the country (a nice added benefit I think).

As long as you are a healthy human being (and not on any meds...particularly anti-biotics, humonia (aged so that the urea has hydrolyzed to ammonia) is IMO a wonderful supplement (particularly is you are low on nitrates).

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