Questions I am starting out with

Crossposted from Facebook, where I originally posted.

I need advice! I know a lot of you out there are spectacular gardeners, and I feel slightly lost.

Pretty soon, I will have five raised beds in my yard. Two in partial shade, for flowers and for herbs, and three in direct sunlight. The three in direct sunlight are 4 ft x 8 ft and have 2.5 ft around so they can be accessed easily.

Here's what I'm thinking. Any reason not to go this direction?

Direct Sunlight #1 - Tomatoes, a pepper, squash, zucchini
Direct Sunlight #2 - Greens! Lettuce, spinach, kale, green beans.
Direct Sunlight #3 - Melons, cucumbers (desperate to find lemon cucumber, hope I can grow it here, a flavor from childhood).

The Square Foot Gardening site uses a mix of 1/3 blended compost, 1/3 peat moss, and 1/3 coarse vermiculite to fill the beds. The Clemson extension site says to work in a 2- to 3-inch layer of organic material such as compost, ground bark, leaves or manures. Adding an additional source of nitrogen will help the organic material break down. What would you do (or are these the same?) P.S. what is vermiculite?

Where would you purchase soil/compost/peat moss where it could be delivered? If we buy bags it will be multiple trips.

Both sites say to interplant vegetables instead of grouping them by type like I want to do aesthetically. Is this really that important? Are there any magical pairings of vegetables the way that you want to group some livestock together but not others?

What grows really well here in the south?

Would you start with seeds or seedlings? For either answer, where do you like to buy? Is there a good place to find heirloom seeds locally?

Both sites also said that raised beds stay warmer so I can plant earlier. When is earlier? Now?

If your advice makes my garden do really well, prepare to be fed with chocolate zucchini cake and salsa.