Time is now to start tuberous begonias

Ah, but for tuberous begonias, it doesn't seem to matter. They will sprout and grow given a good south-facing window. Of course, lights wouldn't hurt. Either way, now is the time to start buying, if not planting begonias of the tuberous variety.

What gardener doesn't love seeing those big boxes of tubers all lined up at nurseries. This is the start of the indoor growing season as far as I am concerned.

The pictures on those boxes of what the particular tuber's flowers will look like are hard for the newbie to believe possible. You look inside the boxes and you can't believe that what is in there could possibly ever bear such beautiful flowers.

Its true, however, they do grow and actually end up looking like those pictures, all from a "just add water and light" kind of plant. What's more, the cool and damp conditions we normally curse Southcentral for having, are so ideal for growing them, that our begonias are probably the biggest, most colorful, highest producing tuberous begonias in the world. Just ask any tourist or gardener who has seen the collection at the Bake Shop at Alyeska.

Easy and fantastic. How can you go wrong? Well, for starters, by not buying them now. You can start them anytime in the next month or so, but they go fast, especially the big, plump ones, so buy them now. Don't go overboard unless you have the room indoors. These are generally large plants, one per 12 inch container, ultimately.

Each tuber has a depression or concave area on one side. Look inside and you may see tiny, pink stems already sprouting. If not, this hollow is where they will sprout. The stems are fragile, so treat them accordingly. Don't worry if you don't see them. A few weeks in daylight and they will appear.

There are two basic types of tuberous begonias available. Some tubers produce plants with flowers suitable for baskets and hanging containers. The others are uprights and can be planted in containers or in gardens. Each comes in a variety of shapes, forms and colors. Decisions, decisions. Still, they are all the same easy tuber to grow. Make sure to write the variety of the tuber on the bag. Tubers can last 25 years or more. Your kids will want to know what the name was.

You will also need soil that drains and is full of organics. Compost with a bit of sand is ideal. This should be pre-moistened and then used to fill four inch pots to within an inch of their rims. Keep the depressed side up and push the tuber into the moist soil just up to the rim of the depression. There is debate about whether it is best to fill the hollow with soil. For now, don't. The roots grow from the sides and bottom of the tuber, not inside the depression.

If you are planting in a flat, tubers should be about two inches apart, and the flat filled to the top with soil before you press in the tubers. In either case, the soil should be slightly moist. Slightly means mostly dry. Don't over water. The tuber has moisture in it. And put water on the soil, not the tuber.

A seed germinating mat to heat the soil is useful and seems to speed things along. Warmer temperatures will encourage sprouting as will exposure to the best light available.

Flat-started tubers will have to be transplanted into pots when they develop two leaves. Cut the soil in the flat like brownies in a pan and transplant without disturbing the roots. The flowers, incidentally, will face the same direction as the leaves are pointed.

Tubers started in pots will also need to be transplanted into larger quarters again once the plant has developed a few more leaves and the roots start crowding the walls of the pot.

If you already have tubers at home, perhaps still in last year's baskets and containers, now is the time to take them out and rejuvenate them. Start them in fresh soil in smaller containers as noted above.

Jeff Lowenfels is a member of the Garden Writers Hall of Fame. You can reach him at teamingwithmicrobes.com or by calling 274-5297 during "The Garden Party" radio show from 10 a.m. to noon Saturdays on KBYR AM-700.