Q - I have acorns from a beautiful oak. I picked them up off the ground and put them in a jar, in a cool place for spring planting. Can you suggest anything that might be helpful?

A - Acorns of most species of white oak should be planted in the fall immediately after being collected. Those of black oak species can be planted immediately or stratified (stored in moist, well-drained sand or sand and peat for about 90 days at about 41 degree F.) and planted early in the spring. When planted in the fall they should be mulched with about two inches of leaves or straw held in place by chicken wire. Remove the mulch in early spring after danger of frost is over.

There's a strong possibility insects may have damaged the acorns while they were on the ground. If so, they will never germinate.

Q - I picked my grapes early before the birds took all of them and let them ripen in the sun on a windowsill. They taste awful. What went wrong?

A - The longer grapes remain on the vine, the sweeter they will be. They should not be picked green because they will not ripen any more after that. A taste test is the best guide to ripeness of grapes. Pick the fruit when the flavor suits your taste. White grapes develop a yellowish-green skin when ripe, blue varieties a deep blue color and red varieties a bright red skin.

When birds start to go after the grapes, put a paper bag over each bunch. They will ripen normally with the bag there.

Q - I have a lot of onions in my garden. What can I do to keep them from spoiling after I harvest them?

A - Onions can be stored at around 33 or 34 degree F. in a good dry area and last indefinitely. Wait until the tops fall over and then dig the onions. Let them lie on the surface to dry for a few days and then store them.

Q - The top two feet of my 15-foot-tall Chinese juniper turned brown almost over-night. What could have caused it? It was such a beautiful tree.

A - It probably was due to someone in the neighborhood spraying with a weed-killing chemical such as 2,4-D. With even a little bit of wind, the chemical can be blown and cause serious damage a block away.