sticker, Safer's Soap,
or, if bugs are also a problem, with a liquid organic insecticide
like Red Arrow (a pyrethrum-rotenone mix), eliminates surface
tension and allows the fertilizer to have an effect on brassicas.

Sadly, in terms of nutrient balance, the poorest foliar sprays are
organic. That's because it is nearly impossible to get significant
quantities of phosphorus or calcium into solution using any
combination of fish emulsion and seaweed or liquid kelp. The most
useful possible organic foliar is 1/2 to 1 tablespoon each of fish
emulsion and liquid seaweed concentrate per gallon of water.

Foliar spraying and fertigation are two occasions when I am
comfortable supplementing my organic fertilizers with water-soluble
chemical fertilizers. The best and most expensive brand is
Rapid-Gro. Less costly concoctions such as Peters 20-20-20 or the
other "Grows," don't provide as complete trace mineral support or
use as many sources of nutrition. One thing fertilizer makers find
expensive to accomplish is concocting a mixture of soluble nutrients
that also contains calcium, a vital plant food. If you dissolve
calcium nitrate into a solution containing other soluble plant
nutrients, many of them will precipitate out because few calcium
compounds are soluble. Even Rapid-Gro doesn't attempt to supply
calcium. Recently I've discovered better-quality hydroponic nutrient
solutions that do use chemicals that provide soluble calcium. These
also make excellent foliar sprays. Brands of hydroponic nutrient
solutions seem to appear and vanish rapidly. I've had great luck
with Dyna-Gro 7-9-5. All these chemicals are mixed at about 1
tablespoon per gallon.

Vegetables That:

Like foliars

Asparagus Carrots Melons Squash
Beans Cauliflower Peas Tomatoes
Broccoli Brussels sprouts Cucumbers
Cabbage Eggplant Radishes
Kale Rutabagas Potatoes

Don't like foliars

Beets Leeks Onions Spinach
Chard Lettuce Peppers

Like fertigation

Brussels sprouts Kale Savoy cabbage
Cucumbers Melons Squash
Eggplant Peppers Tomatoes

Fertigation every two to four weeks is the best technique for
maximizing yield while minimizing water use. I usually make my first
fertigation late in June and continue periodically through early
September. I use six or seven plastic 5-gallon "drip system"
buckets, (see below) set one by each plant, and fill them all with a
hose each time I work in the garden. Doing 12 or 14 plants each t