dragnlaw, That white powder you see on almost everything in my photos is
Surround - a brand of kaolin clay that is totally harmless for food crops (it's the kao in Kaopectate!), and is not something that kills the insects, but most of them don't like the feel of it, so they stay off of it. And something else good about it is that it doesn't wash off easily in a light rain, like with DE. And even in heavy rains, the powder on the undersides of the leaves stays on well - the best place to cover, since that's where insects congregate, as a rule. I start early with eggplants (for flea beetles) and okra (for aphids), making sure I get underneath. Cucumbers are another thing it works great for, for all those beetles that are attracted to them.
I keep one sprayer dedicated to just surround, with some potassium bicarbonate added, as a fungus prophylactic. Early on I might spray the faster growing things twice a week, but just the new growth, as it appears, unless it was washed off with a storm. It lasts a long time; even later on, with larger plants, it only takes a half gallon or so to do this once a week, on the new growth, and it goes fairly fast. I learned early on that it can clog the sprayer, so when I fill the sprayer I have a fine SS strainer that I put the powder in (along with the potassium bicarbonate) and wash it through - usually a half cup or so at a time - and I don't have any problems, even after it sits until next time, and settles in the bottom. Just shake it up, and ready to go!
The surround was not cheap, the first time I got it, being in only 5 lb bags, but later I got a deal on a 25 lb bag for less than twice as much! And it lasted me at least 7 or 8 years. I just opened my second 25 lb bag - I fill a 4 gal container with it, and it looks like it will fill it almost 2 more times. I marked it with a date, to see how long this does last!
As for watering, it depends on what plants how often, but all are done with drip emitters, on timers, so water doesn't get on the leaves, and will not wash the surround off at all.
I am taking my hydroponics setup down today, as I have enough basil outside now, and I always have to do this to clean it out. I harvested the last of the chard from it - it would have kept growing! I also got a few more tomatoes ripening, including the first black ones - Nyagous.
Two Nyagous and one Brandyboy F2, ripening, and the last chard from the hydroponics, 7-5 by
pepperhead212, on Flickr