Clay isn’t bad, but you’re going to want to dig in a lot of decayed organic matter. Some mixture of the cheap commercial compost (composted redwood sawdust, around here) and aged chicken manure is pretty good for a start, though I expect I’m going to be buying less stuff now that the worm composting is going well (and taking all our vegetable/fruit scraps and paper shredder output.) If I had a lot to get started at once (maybe when we own a house and I can live my dream of having about 500 square feet of garden), I’d rent a truck and pick up a load of the composted yard waste freely available, even though I suspect it’s less nutritious and full of weed seeds.
I’m less impressed by mulching techniques and materials than most people seem to be. More on that in the future. Though, aside from being lazy, one possible reason not to mulch beds is that it may discourage ground-nesting bees. (See Mulch Madness, One More Deterrent To Beeing Successful).
In a dry climate, drip irrigation is the best thing ever. You can maintain good moisture levels without over and underwatering. You can avoid all the troubles of hitting plants too hard with water or disease related to having the tops of plants too moist. Just about the only thing it’s not good for is sprouting seeds, since you don’t get very even moisture levels at the very top of the soil.
Drip Irrigation for Every Landscape and All Climates by Robert Kourik is a good book on the subject, though I pretty much figured it out on my own beforehand. It’s ideal to avoid lots of connections and just use lengths of tubing that have integral emitters. Also, use a good filter, regulator, and always use a backflow preventer.
Mizuna is just about the only salad green you’re going to grow in the hot dry summer here. Arugula will do okay, but it gets too bitter and bolts easily. Nasturtium is trivial to grow even in partial shade (though you get less flowers that way.)
Give zucchini and tomatoes ample water and lots of manure. As with any fruiting crop, don’t let the zucchini get too mature before picking, or it’ll start to slow down. One zucchini plant is enough for two people unless you really love zucchini. Zucchini (and many other fruiting annuals) need calcium. If they don’t have enough, you get blossom-end rot. With this somewhat alkaline soil, gypsum seems to work (and should help make the clay easier to work). In more acidic soil, dolomitic lime is the standard thing, from what I hear.
Sunflowers are easy once they got big enough to resist slug and snail attack. Growing pole beans up sunflowers works, but I’ll build a trellis next time to space the vines out better. Also, if you’re unlucky, the weight of the beans breaks the sunflower in half. (This is the “mammoth” sunflower I’m talking about — 7 feet tall even with shade for part of the day.)
As for slugs and snails, the baited iron phosphate granules (Sluggo is one brand) seems reasonably effective and is essentially harmless to people, pets, and plants in the quantity used. Sprinkle on plenty at least monthly. Most of the trouble I had was with small plants as they sprouted — once things like beans and sunflowers got bigger, they have reasonably snail-unfriendly surfaces. And the zucchini is downright pest-unfriendly — the stems give me a temporary rash on my arms, though callouses on the my fingers make them okay to handle that way.
This was all the stuff in the ground, which I find vastly more enjoyable for growing annuals, compared to fiddly containers. More on the container stuff next time…