Overwatering: Yellowing leaves


I noticed some of my tomato leaves started turning yellow. I saw this in a few other plots as well. I took my sad leaves home and consulted the internet for some diagnostics.

It appears to not be disease or bug related. Instead: overwatering.

Two things can be contributing to overwatering in our plots:

1. The compost we received in spring was ‘heavy.’ It was mixed with clay, and that clay holds water (and nutrients) very well. So that means it needs less water. I had our original (without compost) soil tested and it was ‘sandy loam’ which is great, but has a hard time holding water and nutrients.

2. I added wood chips to my plot to keep moisture in, but didn’t adjust my water schedule accordingly. Keep that in mind if you have woodchips or weed mats.

What happens from overwatering?

When you overwater, the roots get ‘suffocated.’ It inhibits the uptake of oxygen and nutrients. If prolonged, it can also cause root rot. To fix it: let the soil dry out and water more sparingly. Also cultivate the top soil to aerate it.

Is clay soil good or bad?

It has a lot of benefits: it holds water, meaning we can cut back which is great for the drought. It also holds nutrients really well so you don’t have to fertilize as often, and when you do fertilize it lasts a lot longer. Lastly, roots like clay soil because they can get a firm foundation (unlike sandy soils that shift all the time).

The bad & how to fix it: it compacts much easier than sandy soils and can suffocate roots. Cultivate the soil to improve aeration. Cultivating the dirt is just using those hand-rakes to turn up the dirt a little and mix air in. And a tip from fellow gardener Rusty, cultivating the soil disrupts a lot of the pest cycles.