Ask the gardeners

I bought some of the Explorer potato plants from a garden store last spring, planted them in mid-May, and dug the results in mid-October. While they were delicious, some were as small as marbles, others as round as golf balls, and still others were long and irregular. Could you comment on your experience with Explorer potatoes grown from seeds? Our experience was much the same. Explorer is just that - an exploration of growing potatoes from seeds instead of tubers.

Remember, they are not hybrid seeds; therefore the resulting tubers represent the shapes and sizes of the parents. We were warned about this by our professional potato-growing relatives. Undoubtedly, there will ultimately be hybrids.

One other complaint is that tubers were green skinned. Our potato background taught us to plant our transplants 4 to 5 inches deep, but those folks who treated them like tomato plants got potatoes forming too near the surface and the sun turned them green. These are bitter and not edible.

Last spring friends gave me, a second-grade teacher, a fluorescent light with adjustable legs, especially for growing plants. We grew tomato plants and some flower plants for transplanting outdoors and the children were thrilled. Our question is: What small flowering plant could we grow from seeds that would be in bloom by Christmas; or if that's too soon, by Valentine's Day? For economy and infallibility you can't beat dwarf French marigolds, but better allow 8 to 9 weeks for them to flower after sowing seeds.

Dwarf zinnias, such as Peter Pan (somewhat expensive) and Thumbelina, will bloom in 6 to 8 weeks. Be sure someone will be able to care for them over the holidays and make sure the temperature doesn't drop below 55 degrees F. for any length of time.

We commend you for introducing your children to the joys of growing plants.

We have a row of evergreens that are exuding a sap or resin on the branches. The branches are turning brown and needles are dropping. The problem seems to be only on the bottom branches. Spruce and other conifers - pine, balsam, Douglas fir, larch, and hemlock, for example - are sometimes susceptible to cytospora (sy-tah-spora), which affects the lower branches and then progresses upward.

The needles turn reddish brown and drop, resulting in naked lower branches.

You can prune out these branches, pruning only when the needles and bark are dry. Make each cut flush with the main trunk. The problem is associated with older trees. Also, trees that have been weakened by an injury are more susceptible.

Lawn-mower injury is often a contributing factor.

If you have depended on the evergreens as a windbreak, you can plant smaller evergreens that are resistant to cytospora (arborvitae, junipers, etc.), in front of the large trees, or you can use deciduous shrubs. Plant about 10 feet away from the old trees.

If you would like a question about your garden, inside or out, send it to the Gardening page, The Christian Science Monitor, One Norway Street, Boston, Mass. 02115. Doc and Katy Abraham are nationally known horticulturists, authors of several books on gardening, and greenhouse operators for 25 years.