I recently tested my soil and the findings were that the soil is very low in nitrogen and phosphate. The leaves on my plants are yellow (the bottom leaves yellowed first), and they are not growing as well as the plants of the same species and from the same nursery that are growing in the nursery containers. I use Sta Green Garden soil mixed in with my regular soil. I want to know how to increase the nitrogen and phosphate organically so that I don't overdose the plants or burn them (or the new seedlings) with a commercial brand. I used Bayer Rose this morning and watered it in. My marigolds and vinca seem to be infected with botrytis blight. I cut them down. I don't use any mulch because I have so many flowers in the garden that there is very little exposed ground to mulch. HELP
Did you submit a soil sample to a laboratory or did you use a home test kit? If you submit a sample to a lab and indicate the type of crop you want to grow, the lab will provide recommendations for you. We would also be happy to help you interpret a soil test report. You can upload a picture of the soil report and attach it to this reply.
We are not sure what you mean using Bayer Rose. For an organic source of nitrogen, you could use cottonseed meal, alfalfa meal, or soybean meal. Take a look at our publication on soil amendments and fertilizers for organic fertilizer options.
The plant in your first photo looks scorched. This symptom can occur either as a result of sunburn or fertilizer burn from foliar applied fertilizer. The second two plants (with yellowing older foliage) look they could be lacking nitrogen. In basil, downy mildew can also cause a yellowing like this. Check the underside of the leaves for signs of mildew. https://extension.umd.edu/hgic/downy-mildew-basil
In many cases, an annual application of compost mixed into your soil can supply sufficient nutrients (nitrogen, phosphorus, potassium -- and micronutrients) for your plants.
Thank you so much for the response. Bayer All in One - Rose and Flower Care is what I used on the roses. With regard to sunburned plants. Any advice? Should I cut off those leaves, or just let them be and hope that it recovers when we have a few cooler days?
With regard to the sunburned plants, you can prune out the damaged leaves. They will not recover from that damage. If you see healthy new growth on the rest of the plant, it should be fine.