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Hi all,

I've noticed several of my trees and shrubs looking a little pale this summer, some of the leafy ones are showing yellowing of some of the leaves. Given that I have sandy soil it's possible it could be a nitrogen deficiency, however several soil tests have shown I have neutral to slightly alkaline soil so it might also be chlorosis. I would like to address both possibilities while it is still summer and I have time to notice if the plants are responding before fall is here. I started some grass clipping tea today, I filled 6 5-gallon pails about 2/3 full of fresh clippings and filled with water, I plan to dilute 6 to 1 to get 36 pails and will use this in a couple days for a nutrient boost. My question is, I have some aluminum sulfate on hand that I was planning to use in the fall to lower the pH on the trees and shrubs that obviously don't care for the alkaline soil - can I use some of this and mix it into the grass clipping tea? My well water is also slightly alkaline and I'm thinking it would help to have a bit of an acid solution for the tea to hit both problems at the same time. My understanding is that some of the aluminum will precipitate to aluminum hydroxide when mixed into alkaline water, is this something I should be concerned about? Would it be best if I dealt with the pH issues in the fall and just used the tea for now? I'm all ears for better ideas as well, especially if anyone can suggest something non-chemical I can use to acidify the soil that will dissolve in water. I have some misgivings about aluminum sulfate based on what some people have been telling me.

Thanks

if the soil is only slightly alkaline it should not be a problem. The usual way to lower pH would be with sulfur. It would take 6 months to see the result. Aluminum can bind phosphorus if it is in large amounts. I would use elemental sulfur. It is available and allowed in organic production. For a nitrogen boost, I would use sulfate of ammonia since it would solve both problems, but you can use fish emulsion or blood meal to add nitrogen. They are relatively fast organic nitrogen, but you would need to use them in quantity to get the same amount of readily available nitrogen as sulfate of ammonia. Weekly fish emulsion and a combination of blood meal and kelp meal would be organic choices. If the leaves are yellow on the bottom and pale on the top, and not showing dark green veins then it is more likely to be a nitrogen problem. Chlorosis would show dark green veins on the leaves and that would most likely be an iron or some other micronutrient deficiency. Again I would give a complete fertilizer with slow release nitrogen with micronutrients. If you want to do this organically you will need to determine what your deficiency is and how to correct it.

To get a better understanding of what fertilizer you need, get a soil test. You can get soil test done relatively inexpensively by the nearest land grant university near you. Ask for organic recommendations if they have any, otherwise they will only give you synthetic recommendations. Organics are hard to use for specific elements since they are rarely "pure sources" and the quality can vary from batch to batch and leach with age. If your soil has excess amounts of some nutrients, it may be hindering the uptake of other nutrients and you don't want to add more of what you don't need since it would only make the problem worse. A basic test for pH and basic nutrients is what most people will get.

https://extension.psu.edu/using-organic ... nt-sources
https://bigpictureagriculture.blogspot.c ... -leaf.html

Thanks for the reply, I think I'll try the elemental sulfur this fall and see how things are in the spring. Based on what you said, I do see some plants that are lacking nitrogen, and some plants that are chlorotic (green veins). I saw some slow release fertilizer that uses sulfur coated urea, would this work well for both problems? Is it too late to apply this fertilizer this season, even if the plants are showing deficiency? I expect a first frost around 5 to 7 weeks from now where I live, and I will be protecting less hardy plants through the winter.

It will help to give the plants sulfur and nitrogen. It all depends on the pH of your soil and how much sulfur is required to get the soil into the range you want. Slow release nitrogen is a good choice for most situations, but if the plants are showing symptoms of nitrogen deficiency, I would use a nitrogen source that is a little faster but not a high number like fish emulsion, blood meal or a water soluble fertilizer as a boost.