A new gardener with new garden problems: clay, heat, and yel

[bananabat]

Hello, I'm new to this forum and to the gardening world in general. I'm glad there're folks out there dedicated to helping struggling hobbyists.

The trouble I'm having is that the lower leaves on my plants (summer squash, var. tomatoes, sweet peppers, cabbage, broccoli) are yellowing. I understand this is indicative of nitrogen deficiency. The real problem is, well, the real problem requires some background information:

I live in the Brazos River Valley in Texas, which means I'm growing in soil that is extremely heavy in clay. I tilled in a good amount of compost, but the clay still predominates. On top of that, the weather here has been very hot - consistently over 100F each day. My plants are quite young and wilt within hours of watering in this heat, so I've been watering lots! Too much watering, I understand, can contribute to nitrogen deficiency.

So I seem to be able to do no right. I let the plants wilt in the heat, or I water too much and leech away all their nitrogen.

What can I do?

[stella1751]

I generally have one or two yellow bottom leaves on my peppers. My squash and cucumber bottom leaves are old, beat up, and slightly yellow. My tomatoes don't have any bottom leaves (I pruned them off). You might not have a problem if it's just a few yellow bottom leaves. Can you post a photo?

I'm no expert, but I always thought that nitrogen deficiency or over-watering made all the plant's leaves go yellow?

[bananabat]

I'll see if I can borrow a friend/neighbor's camera for some pics later today

I wouildn't be so concerned about a few yellow leaves, except that the plants are still so young, in some instances their few yellowing leaves are all they've got. The leaves on some of the other plants aren't so yellow as the squash leaves, but aren't looking like green, happy, healthy leaves either. I figured they may just be a few steps behind the squash?

[rainbowgardener]

It is stressful conditions. If you can keep adding compost, either troweled in or as a top dressing, that should help hold water in the soil better. Then add a good layer of mulch for the same reason. Then consider some shade cloth. Most of the warm weather veggies like temps between 70 - 85. When you are talking triple digits, only hard core desert plants like that. With mulch and shade cloth (also known as row cover - very light, loose weave cloth that doesn't block all the light, but filters and diffuses it -- you can get it at any garden store), you should be able to water a lot less, so quit flushing nutrients out of the soil.

Stella is right that it is usual for the oldest bottom leaves to turn yellow and die off after awhile. If that is all that is happening the plant should have healthy green leaves at the top.

Also you mentioned cabbage and broccoli. They are COOL weather crops that don't like the heat at all. If you are in zone 9 or 10, you would want to plant cabbage and broccoli seeds now or in Sept, to grow through the fall and winter.

If your plants are "quite young," it sounds like you started late for the warm weather crops (squash, tomatoes, peppers). For next year, if you are starting from seeds, you'd want to start them in Jan-Feb. In your climate you might be able to put plants in the garden sometime in March.

[bananabat]

Alright, here are some pictures.

This one shows the yellowing of the older leaves on a squash plant and is the best (worst-looking) example
[img]https://img216.imageshack.us/img216/613/39584861.jpg[/img]

As I was walking through the garden this morning I noticed some other things that looked abnormal and snapped shots of them too (my phone is my camera, so my camera takes lousy pictures). Please let me know if I have anything to worry about from these pictures too. I suspect I have.
[img]https://img219.imageshack.us/img219/7725/88199699.jpg[/img]
[img]https://img231.imageshack.us/img231/172/42784730.jpg[/img]

f your plants are "quite young," it sounds like you started late for the warm weather crops (squash, tomatoes, peppers).

I got started as soon as I could (just moved in here), but according to my county's planting guide, I'm within the accepted dates, at least for peppers, squash, and tomatoes. Not so much for the cabbage and broccoli. I got overzealous at the farmers market is what happened there...