Q - Small tomatoes are growing on my Irish potato plants, at least that is what they look like. Isn't this very unusual?

A - No, not really. After the potato plant blooms, seed pods form. They look very much like small tomatoes. In many areas, summers are too hot and dry for development of seed pods.

Q - My neighbor picks his tomatoes when they turn pink and takes them indoors to ripen. He says he gets better results that way. Do you recommend it?

A - For the best flavor and color, tomatoes should be harvested after they are fully vine ripened. Thid is one of the main reasons for growing them, to get that special flavor which you cannot find in those sold in most markets.

Of course, if there is a risk that someone may appropriate them in the dark of the night, that is a different matter.

Q - How can you tell when Irish potatoes are ready to dig?

A - Potato tops usually turn brown when the tubers reach maximum size.However, the tubers are large enough to eat before the tops die back. Try a few. When they are large enough to satisfy you, they are ready.

Q - How can I store Irish potatoes to keep them firm? Last year I put them in the basement and they spoiled.

A - Without cold storage, you cannot keep Irish potatoes long without shrinkage. The cooler they are kept, the better.

Digging is important to storage life. Do it on a cool morning, if possible, keeping potatoes out of bright sunlight after they are dug. Discard all rotten or severely damaged ones. Cure them at a temperature of 70 to 75 degrees for one to two weeks and then store in complete darkness at 50 degree to 60 degree.

Q - I've been trying to grow English ivy under my Norway maple tree. Grass won't grow there. The cuttings I planted just shriveled up and died. What is the secret of getting them to grow?

A - Root the cuttings first in a shady, moist place and when they are well rooted, transplant them under the tree. Dig a rather large hole for each one and fill with good soil. This will give them a chance to get going good. Keep them well watered during the first year while they are getting established.

Q - Can petunia cuttings be rooted? I have a beautiful one and I'd like to have some plants to grow indoors this winter.

A - Petunias root easily. Take cuttings about four to six inches long. After they have rooted and made some growth, pinch them. Without pinching each may grow straight up as one stem and become lanky. Pinch out the growing tip and the plant becomes bushy. When new branches develop, pinch them also. The petunias won't do much for you indoors unless you can grow them for 12 to 14 hours under artificial light each day.

Q - My strawberry plants have developed runners that are practically taking over the garden. Is this normal, and what can I do about it?

A - It is normal for strawberry plants to produce runners until the first freeze. These runners will provide flowers and fruit next spring. If there are too many runners, thin them back. That won't harm the rest of them.

If you have a question for Tom Stevenson, write to him at the Weekend section, The Washington Post, 1150 15th St. NW, Wahington, D.C 20071.