I live in NE Houston. I have a small raised bed where i just planted out a few tomato plants a couple weeks ago. Before planting out, I raised them from seed in my greenhouse. I hardened them off properly, and then planted them out, at the risk of a frost (which so far hasn't come!). Anyway, I've begun to notice they are turning a little yellow, as if they have a nutrient deficiency. I just built the raised bed, and the profile is as such: dug under the existing soil, 4" of dried horse manure, 2" of leaf litter compost, 3" of "garden soil" (a sandy, mulch ridden dirt mix) from the local nursery. I don't think the plants are really all the nutrient deprived. I have since also treated them with a nitrogen rich foliar feed, and a drench of the same composition.
My theory is this: due to the soil being still cool, the plants have essentially ceased growth, thus ceasing photosynthesis, and losing color in the leaves. I'm hoping as the soil warms a little more they will start to green up. Has anyone else seen this before? Is my guess a valid guess? Please let me know. I'm planning on getting some black plastic to lay around the base to help absorb some of the sun's heat and hold it in the soil. Thanks in advance.
Backyard Gardener Houston, TX