How to diagnose stunted garden plant growth/lower yields?

Asked July 2, 2020, 7:08 PM EDT

Hi, I have several plants in my garden that aren't as bushy as I think they should be and I'm looking for help diagnosing the problem. My tomatoes, peppers and marigolds are all very tall, but are not very full (wide). My zucchinis, summer squash and cucumbers are also smaller than usual. They are all producing flowers and fruit, but I suspect my yields are much lower than they could be if the plants were bigger. I grow all of them in raised beds and add compost to my garden every year. The peppers are in a raised bed inside a greenhouse where it's much hotter than outside. I had this issue last year, but not as pronounced. Everything is watered using drip irrigation. The garden gets several hours of direct sunlight from the east and south, although it is shaded in the afternoon by a neighbor's tree in the south. I'm thinking that other than possibly not getting enough direct sunlight, it might be an issue with soil PH or nutrients. So my questions are: 1. Does extension do any soil testing for home gardeners? If so, how would I go about that and what are the costs? 2. If I was to buy a soil test kit from a retail store, are there specific ones that you recommend? 3. Are there other possibilities that might explain why the plants grow tall but don't fill out very much? Thank you! Heather

Lane County Oregon

1 Response

Lane extension does not have soil testing capabilities except for pH and is currently unavailable due to the pandemic. There is a lab in Eugene, Eugene Analytical Lab which can do tests. I do not recommend any of the soil tests except the ones for pH. If plants have access to excess nitrogen, that can cause too rapid and less strong growth. It is quite possible to add too much compost which upsets the balance between the various nutrients. This is some very new research. It can especially add too much potassium. That said, this has been an odd year in every way with early spring and full summer alternating, which in itself has caused many problems. A soil test might be a good start since the problem is worse this year than last. You need 6-8 hours of direct sunlight for many crops.