Spinach Leaves turning yellow ?

[Gary350]

I seem to have a great crop of spinach but the leaves have been turning yellow and dying in the past few days. It makes me think there is a nitrogen shortage. I just removed all the dead and yellow leaves. I never had a good crop of spinach so I don't know what to expect.

Online Co-op says, Arizona soil has very little food value for plants, the soil needs a lot of organic material and high nitrogen fertilizer. I have been putting 16/16/16 on every thing so far. Maybe I have been a little stingy with the fertilizer.

I collected 2 pickup truck loads of bagged grass at Road Mart then covered the whole garden with 6" of dead grass and tilled it in. The soil was like a 10" thick mattress but now it has compacted quite a lot. Maybe the dead grass is sucking all the nitrogen from the soil. I can not think of anything else that might be the problem.

The spinach leaves are 6" to 8" across. 4 leaves make a great salad. I have been eating the heck out of it but just can not keep up with it. Maybe the problem is the leaves die because they should have been harvested already? I have 9 spinach plants. Soil and water are both 8 PH.

Double click the picture gets larger. Double click the next picture it gets larger too.

[rainbowgardener]

Dead grass should not tie up N in the soil. Carbon heavy materials like bark chips do that. Compacting could be part of the problem and grass does tend to form heavy mats.

Some yellowing of older leaves if they don't get harvested is normal.

But I expect the issue is your soil pH:

Spinach can be grown successfully on a variety of soils, but a fertile sandy loam high in organic matter is preferred. The soil pH should range between 6.4 to 6.8. ...If the pH is too high, leaves may have a yellow color referred to as chlorosis.
https://www.ces.ncsu.edu/hil/hil-8017.html

If it is chlorosis, often that shows as yellow leaves that still have green veins.

the same article says: Spinach requires a high level of fertility, especially nitrogen. But it sounds like you are using plenty of that since it says: Apply 3 lb of 10-10-10 per 100 ft2. Sidedress with two or more applications of 0.3 oz of 10-10-10 per 10 ft of row

[imafan26]

Most plants like the soil slightly acidic and up to pH 7.5. A pH over 8.0 you can grow cabbages and baby's breath well. Some plants do not tolerate alkaline soils at all like azaleas and gardenia.

Spinach is sensitive to pH. It likes it slightly acidic pH 6.4-6.8, sandy loam. You could grow some adaptable varieties of spinach up to a pH of 8.0

Most Arizona soils are alkaline. It is difficult to change the natural pH of your type of soil. Adding lots of organic matter helps to buffer the pH. If you have plants that cannot tolerate the higher pH, it might be better to plant in raised beds or containers rather than directly in the ground.

https://ag.arizona.edu/pubs/garden/mg/soils/ph.html

https://www.ces.ncsu.edu/hil/hil-17.html

[Gary350]

I do sort of have a raised bed. After tilling in all the dead grass I made a ditch with the shovel then filled it with bags of compost manure from Lowe's. The Spanish plants were doing great when they were smaller but now they are having the yellow leave problem. OK so maybe the roots have grown down into the toxic soil and that is the problem. I put 5 gallons of water in a bucket it took 1/4 cup of vinegar to lower PH to 6 testing it with PH paper. Then I mixed in 2 tablespoons of nitrogen fertilizer. 2 tablespoons is not much but I don't want to over dose and kill the plants. I will water the Spanish for a while with this to see what happens.

I like AZ winter weather for gardening but I worry 10 hours of sun light per day is not enough full sun for some plants. It is rare to have clouds here so maybe 10 hours of our type full sun is = to 15 hours of cloudy sky full sun. My garlic is going great. It was 78 degrees yesterday that is about 5 degrees above average.

[digitS']

Pretty good looking garden there anyway, Gary!

High pH doesn't allow iron to move into the plants easily. It is a little different from a lack of nitrogen but the look can be somewhat the same.

I suspect that it is the "humic" acid in compost that helps with this problem. I wonder if this would be a good place to use compost tea. . . Anyway, your local garden center may have sulfur and recommend its use.

Steve

[Gary350]

Pretty good looking garden there anyway, Gary!

High pH doesn't allow iron to move into the plants easily. It is a little different from a lack of nitrogen but the look can be somewhat the same.

I suspect that it is the "humic" acid in compost that helps with this problem. I wonder if this would be a good place to use compost tea. . . Anyway, your local garden center may have sulfur and recommend its use.

Steve

All the fertilizers and plants foods sold in this state all contain 8% to 10% sulfur. I get sulfur even if I don't want sulfur. Even the nitrogen fertilizer contains sulfur. Water is loaded with iron the toilets, tubs and sinks all turn rust orange within a month. The high priced cleaners do not remove it but muriatic acid will. Swimming pool acid is 29% hydrochloric acid and cheaper than toilet cleaner.

I fill a 5 gallon bucket 1/2 full of compost cow manure then fill it with water. 2 days later the water looks like coffee. I water the plants with that and they do good.