In your area (unless Ca is Canada), peppers or eggplant might be one of your better bets.

You can technically do almost everything that's a summer crop, but it's getting near the time where the heat beats down on bud/flower/fruit formation. Tomatoes are good if it's not too oppressively hot during your late-July/August.

Okra, squash, melons, yardlong beans (not much production out of 1 pot), and tomatillos can handle extreme summer heat if that's an issue. Larger vine melons might enjoy more than 5 gallons of soil to grow in.

thank you so much for the help.....I do have some shade cloth I was going to put up when it gets over 90( we are in california in the high desert suuupppper hot). I just have quite a few extra : cucumber lemons, butter nut squash, scallop squash, banana peppers, eggplants that I just dont know what to do with I have several in the ground already but have extras ( I have given away all I can) and I dont want to( will not let them just die) so I was hoping to put out a bunch in 5 gallon buckets along my drip system; just want to make sure they can grow "somewhat" happily and produce fruit so I can harvest seeds for next year..I have 22 nona prize tomatoes that I bought seeds for in '06 that i thought "oh none of them will come up" I had all but 2 germinated and are now needing to be transplanted. I had heard that tomatoes need more room then a 5 gallon bucket but I do have an early girl that is in maybe a 2 gallon pot and is overflowing with tomatoes

Yep, I do peppers and eggplant in 5 gallon containers, they seem to do better for me contained than in the ground.

I put an extra squash in one but production was so horrible, I'm not doing that again.

I was just looking I do have a few 10 gallon grow bags left over from last year. I wonder if the squash would do better in those?

With squash you need to plant at least 2-3 in order to get enough flowers for pollination to fully occur. It can happen with just 1 plant, but you're counting on the plant to have both male and female flowers available at the same time. The more plants, the better the chances of full pollination of fruits to occur. This also goes for melons and to an extent tomatillos.

Just about anything will go in 5 gallons, except large vegetables. Tomatoes will not do well, and squash, cucumber, melon and watermelon are out. Eggplant, peppers, summer greens such as amaranth or malabar spinach, and okra, given your situation and time of year, are probably OK.

don't listen to That spinach works great in 5 gallon buckets. Check the web And tomatoes are at the top in 5 gallon buckets again the web

What I have grown in 5 gallon buckets and worked:
Tomatoes (determinate or dwarf types do better than indeterminates)
Peppers (both hot & sweet)
Eggplants
Sweet potatoes (you will get 1-2 big potatoes and lots of little ones)
Zucchini (but look for ones meant to grow in containers. Jackpot is the one I grow in containers)

I prefer to listen to actual local gardeners and extension service information than relying on the web. The web is a great source for information but also full of bogus information. Get local input from actual gardeners would be my suggestion for in ground and container gardening.

Agree, the web contains far more useless info than useful info and is buyer beware. Especially so with (dare I say it?) YouTube.

Just because something can possibly be grown in a 5 gallon bucket doesn't mean it should be. Indeterminate variety tomatoes is a good example. If a plant's fully developed size is way out of proportion with its container then it will do poorly.

I agree that small dwarf tomato varieties, most pepper plants, and many leafy greens will do ok, not great but ok, if given ideal care and feeding and if a small amount of produce is all you are after. Otherwise the answer is simple, use a bigger container.

Dave

I agree with Dave, even though I do plant 2 or 3 tomato plants in 5 gallon buckets every year to get some extra early tomatoes.

I can haul them in and out as needed weather wise and get tomatoes at least a month early. They peter out extra early too, because they get root bound. But I think it's worth it because I get fresh tomatoes in early to mid May instead of the normal early to mid June.

I had bad weather and my in ground tomatoes will probably not be ready until late June this year, I couldn't plant them until 2 weeks ago. But I've been eating the tomatoes from 5 gallon buckets for 2 weeks now.