I have heard on more than one occasion a gardener, or a person who eats out of someone's garden, say that there is no such thing as too much broccoli. I have to agree. Broccoli is one of those unfortunate vegetables that take a fair amount of space for the ratio of edibles they produce. Some people swear that broccoli leaves make excellent soup, so you have to count more than just the floral head as part of what you're getting out of a plant. However, a garden takes so much effort one should not eat what is growing there just because it's growing. One should, rather, grow and eat the great delicacies. Fresh, crisp broccoli heads that have come through the first couple of October frosts are such delicacies. Now is the time to be harvesting fall broccoli. You can leave it a while longer in the garden, but it should be achieving its peak just about now, and that is the very best time to pick it. It won't grow much more anyway, because the weather is getting steadily cooler, and most plants need warming trends to stimulate growth. Of course, the obvious advantage of encouraging a fall crop of broccoli is that this is really the only time of the year that giving broccoli the kind of space it needs to do best doesn't seem like a sacrilege. There's always so much one wants to plant in the spring and so little place to put it all. CULTIVATING CABBAGE: Most fall cabbage is not ready yet. Neither is cauliflower nor Brussels sprouts. These will do fine for a while longer. Leave them alone until they are of a size that demands picking. Spring-planted sprouts are certainly ready, however, and should be picked now that they've sustained a frost. POD-HAPPY: Another wonderful green vegetable that one cannot have enough of is peas -- of every size and shape. Like many thousands of gardeners in the last couple of years, I have become an unyielding fan of the Sugar Snap, which has no equal. Even the aspect of it that gets the most criticism -- the fact that it grows so tall -- can be seen as an advantage when bending over to harvest it. And now is the time to be picking peas. A few more weeks and the weather will wipe them out. Pick them as soon as possible after they have matured. Sugar Snaps have a number of mature stages, from the tender young, unfilled pod to the fully mature pod, bulging with fat peas. Even with these cool nights, peas will be blooming and setting fruit. JACK-'O-LANTERNS: Harvest pumpkins this weekend for jack-'o-lanterns. They should be allowed to age a few days before carving. Put the fruit in a dark corner of an unused (cool) room, and by next weekend, it will be ready to carve or store in a more permanent place for the winter. They will keep a long time in a shed or garage where they will be protected from all but the worst freezes. DAHLIA DOINGS: This weekend is also a good time to dig up spent dahlia roots. They are easy to forget once they've quit blooming, and they will not survive winter in the ground, no matter how much they are mulched. The roots will have multiplied over a summer's blooming, so when you're digging them, keep the spade out and away from the plant, allowing about a foot all around it. Shake off all the dirt from the root but leave part of the green top. This should be allowed to dry naturally in storage and then crumbled off later. The ideal way to store dahlia roots is in a peat and vermiculite mixture, about two-thirds peat to one-third vermiculite. Put the mixture in a box large enough to hold all roots so that they are not touching. If you want, at this time, you can divide the roots, leaving three to six tubers to each crown. Some of the crowns will have as many as 12 or 15 tubers protruding from the crown, if put in as roots in the spring. If you planted them from seeds or started seedlings, don't divide the roots this year. HOT POTATOES: Like dahlia roots, the potato is another subterranean dweller that is all too easy to forget. Books claim that they will keep nicely in the ground over the winter. Too often I have taken this sage advice only to find a pulpy, frozen mess in early spring after much rain and winter temperatures in the 20s. Be on the safe side. Dig them up this weekend and store them, preferably in sand, in a large box or barrel. They must be kept out of the light or the skins will turn green and cause stomach aches when you eat them. In the spring, if you haven't used them all, recycle what's left by quartering them and planting them to produce more potatoes. It'll save you the cost of buying seed potatoes and they won't have been powdered with those disease-resisting chemicals. Experience has shown that those chemicals are not necessary to a good crop.