Can you recommend a service for soil testing that includes micronutrients?
I have a garden in Riverdale which was designed by a former owner of the house. In spite of loading it up with new soil and compost this year, plants do not seem to be thriving and some are showing signs of intervein chlorosis. There are large trees around the garden (huge silver maple, katsura, redbud, Japanese lilac, which are likely part of the problem and there is in-ground irrigation, which I have read can also exhaust nutrients.
I am fertilizing with water soluble fertilizers and have added Epsom salts to see if magnesium deficiency is a culprit, but so far no noticeable improvement.
I am thinking that I really need some thorough soil testing to figure out what to do next…
Any advice would be appreciated.
Thank you for contacting Toronto Master Gardeners.
It sounds like you have a beautiful garden space and have been working hard on your soil. Soil is such an integral part of the success of the garden which is often overlooked.
There are many aspects of soil to take into consideration. As you have mentioned the nutrients are a key factor in soil. You will need to also take into account the texture of your soil. When you take a hand full of soil does it clump up when you squeeze it or does it crumble? Is the garden well drained or are the roots sitting in water at times?
Soil needs to form aggregates ( small clumps) to be able to retain water, oxygen and nutrients. Adding fertilizer can help but the soil needs to be able to retain those nutrients and not get flushed away. Without these aggregates the nutrients will not be available to the plants.
To help the soil create aggregates and hold on to moisture and nutrients, it is best to minimize disturbance of the soil as digging breaks the aggregates down. Leaving the soil undisturbed as much as possible encourages natural formation of soil aggregates. You have added compost which is a good step and helps increase the organic content of your soil. Adding mulch at this point will help the garden hold moisture in, decreasing the need for irrigation which leaches the nutrients away. The mulch will over time break down and add to the nutrients and texture of the soil. Undisturbed soil will recolonize beneficial bacteria and fungi increasing the ability to hold on to nutrients.
Having your soil tested is a great step to understanding what you are working with. You should be able to determine the nutrients you have as well at the pH of your soil. The pH can also have an effect of the availability of nutrients.
There are many places that offer soil testing. A reliable facility for testing is the University of Guelph. They supply a variety of services on their website. If you suspect any possibility of contamination of your soil from previous owners they can test for that as well.
Soil is a complex medium. Improving your soil will take time and may require a variety of approaches to get the results you like. The soil testing should help you on that path. Good Luck.