Well, let me answer you by asking you a couple things, what are you trying to grow? Your post says you are in zone 7, and it can get pretty hot and dry during the summer down there.

You mentioned lettuce and cabbage, those are cool season crops. I live in zone 5, and it is just impossible to get my cool season crops like broccoli, cauliflower, radishes, spinach, carrots, and ANY head lettuce to keep it together in the summer. If I want any of those crops I have to do a spring crop that I start very early (January), and a fall crop that I start in mid july/august. Cool season crops won't set the kind of vegetable that you are looking for in the heat, they will "bolt" and try to flower and set seed. Broccoli for instance, once it sets flowers and tries to seed, it tastes very bitter.

warm season crops will do better in the summer heat, provided they have an inch of water a week (use a rain gauge on the ground and a good sprinkler to measure). warm season crops are Okra, tomatoes, peppers, corn, beans, cucumber, and mellons.

As for your insect friends, some people on the forums are avid organic/no chem gardeners, and they can recommend many good organic solutions, depending on the type of insect problem you have.

If you are looking for a chemical solution, Sevin works wonders. It comes in either a liquid spray that you dilute, or as a powder that you sprinkle on the leaves. It breaks down quickly in the environment, and washes off which means you will have to reapply it after a rain.

But the answers you are looking for depend on the type of crop you are growing and the type of bug you are dealing with.

As for the tangling, make sure you have enough light from directly above, to encourage them to grow upwards. I have never had good results with lettuce in a 72 cell container, mine tangle too, I usually use bigger trays.

With direct sunlight, you want to gradually expose them to it. A couple hours on a sunny day, followed by 4-5 hours the next day, should be enough to harden them off.

Lastly, with fertilizer, I usually add compost and manure to my garden in the fall, and again in the spring, and if I need more from how the plants look, I will use something like miracle grow every other week, fed as a weak solution (like 1/2 the recommended strength). The answer really depends on what you are growing and what kind of soils you have. Do you have heavy clay that is difficult to manage, or does it have more organic matter with a more rich color like a silt loam?

I think you really need a local mentor to get you started with seeds. Only those where you live know what your growing conditions are and what insects are a problem. Join a local garden group or club or volunteer at a non-profit garden. Al

A good basic resource is the book, "The Vegetable Gardener's Bible", by Edward C. Smith. I still refer to it today. It is a very good resource for explaining growing veggies from seed starting to harvest. I like how the book is laid out in a very easy-to-read format with lots of pictures and helpful charts. I'd highly recommend it as a starting point.

Here is a link that might be useful: Loribees Garden Blog

Note; Watch for birds the love many of the plants you mentioned & can do more damage quicker than bugs.

Thanks all for the great advice,
I want to answer Chris CL. Hi Chris, thanks for all the explanations. I am trying to grow everything you mentioned plus summer stuff.
A month ago I started the spring stuff: lettuce, cabbage, spinach, bok choy, broccoli, onions, and am doing different types. They are what died and got tangled. The last freeze here is around April 11th, so I was going to get them out this week. Only some lettuce and cabbage survived. I guess since its already in the 80s and will be in the 90s by May, I need to wait and do a fall crop as you suggested in say August with the seeds I have left? The nights are still cool say 48 degrees. Let me know cause I would love to get out some green like my brussels sprouts before it gets hot.
Now as far as summer goes I have 17 different types of tomatos, several types of peppers, water mellons, okra, cucumbers, summer onions, and strawberrys. I was going to go ahead this week and start them in cups and aluminum pans with holes in the bottoms of the cups for proper drainage. I also cover the pans, with the seed cups in the them, with Saran wrap until germination. Water melons, strawberrys, cucumbers,and okra I simply seed in the ground. I have to weed soon, and after turning the soil over I was going to add cow manure 50/50 with the soil. Its top soil with red clay underneath. If I do a soil test with my pH soil test kit what range for what I have mentioned do you recommend for optimum grow? I have lime to neutralize if needed. Some of the tomatos and the strawberrys will be grown in very large pots on the back porch.
Last year was my first try and the weather and bugs killed it all. I did most of what you mentioned, but used old bug killer. Where I cleared is overrun with black ants. Funny cause fire ants rule the rest of the yard. I heard some bug that comes out at night could have eaten my greens last year? I will get some Savin liquid concentrate. I gave my plants alst summer an inch a week of water at least, sometimes every evening, and I have a rain gauge. However, the over 100 degree temperatures last year for so long was just too much I guess, I am unsure what to do this year as I expect the same temperatures.
Thanks for the sunlight guide. I did something similiar, but once they got outside the leaves on say the peppers; just drooped in the sun. After I gave up, I actually had small Rutgers tomatos come in when it was October last year?

Thanks again folks and I will checkout that book loribee2

You mention that they get tangled. Are you thinning your seedlings so that each one has the appropriate space for its variety? Also, are you keeping the light source close enough to the seedlings to avoid them becoming leggy?