There are lots of good bargains around on rather ordinary flowers that can do much to enhance gardens that begin to look like melting ice-cream cones now.

I'm not partial to chrysanthemums -- they remind me of the return to college classes, the homecoming game and oversize corsages. But there are one or two daisy-like mums that I'll tolerate, especially in the face of fading summer color.

The mums you're most likely to find in stores won't have bloomed yet, but they'll have small buttons of buds. This is just about the right stage to buy them. Transfer them from their plastic pots to clean clay pots and bury the pots in the garden or put the plant directly into the ground.

There's a lot of debate about the likelihood of chrysanthemums' surviving winter intact outdoors. I'm here to lay those doubts to rest: the plant is so inexpensive and so ordinary that it really shouldn't matter much whether it can be nursed through.

Having said that, however, the answer is yes: Mums are perfectly winter-hardy and, in fact, will burst forth next spring to devour your garden. You may find some giant mum varieties somewhat more delicate, being rather highly bred. These varieties need shelter from wind and chill.

I picked out four pots of daisy mums, for $1.39 per pot, to supplant my kitchen-window hanging baskets of impatiens, which are losing their leaves and blooms anyway. I moved the impatiens to the back porch, where they'll revive somewhat before I bring them in for the winter. After the mums have finished blooming, in about early November, I'll plant them in my kitchen garden, which is well sheltered and faces due south.

If they make it, I may have a battle on my hands to keep them contained next spring -- I'm somewhat ambivalent about that prospect. If they don't, I'll have enjoyed their company for six weeks for less than the cost of one lunch downtown. Can't beat that. HARBORING HOUSE PLANTS: This is the time of year when houseplants that have been enjoying the freedom of summer outdoors must suddenly be as pampered as a new-born child, and when even the most stalwart plant-owner is reduced to the role of neurotic parent. Each fall, my houseplants are plunged into mourning as they enter the living room, and they refuse to emerge from this state until allowed to feel the spring breezes once again.

I know of no tried-and-true way of insuring that this won't happen to your plants, barring the addition of a greenhouse, impractical for most of us. But here are a few tips you may want to follow:

* Check the underside of the pot. If there are roots emerging from the drain hole, the plant is ready to be repotted. Transfer it to a clean pot one size up, which you have lined with a layer of potting soil. You need only enough to fill in the gaps.

* Submerge the entire pot in a bucket of water until all worms (if there are any) float to the top and remove them.

* Cover the soil with aluminum foil and place the plant, upside down, in a bucket of warm, soapy water. Swish around for a minute or so and then rinse the plant off. This will clean off spider mites, aphids and many common insects that you wouldn't want to bring into the house.

* Move plants in gradually. First, hang them in a shady area that gets very little breeze. Then move them in at night only. After a while, if you can, move them in permanently, but give them a few hours outside each day. This is the hardest part, because no one can ever remember to let the plants out, the way you would a cat.

* Keep temperatures relatively sane: A conservation-oriented 68 degrees will suit them fine, and they'll tolerate a much cooler environment.

* Group plants together. Plants enjoy one another's company -- and anyway, when they're deprived of summer weather, misery likes company.