Early spring gardening

By John Fulton

[March 19, 2012]  If you haven't cleaned off perennial flower beds, you may be surprised what is already growing under last fall's dead leaves. It is important to get mulch and leaves off the growing perennials as soon as possible.

Also, the forsythia is in bloom in some places and ready to pop in others. That means, if you were planning to apply crabgrass preventer, it should be applied rather quickly.

The spring garden

While 60-70-degree temperatures get us used to spring and summer, we may be jumping the gun on planting warm-season garden items. Witness the 30-degree temperature drop of the last week. Many annual flowers, tomato plants and other warm-season plants should not be set out until after May 10. When we look at our average frost-free date, we see that it is April 25. About half the time in the last 30 years, the average last spring killing frost has occurred by this date. That also means that about half the time it hasn't.

Of course, the dates are earlier if you use protective covers, such as milk jugs, row covers or wall-of-water types of protection. Usually it is just as easy to wait until the recommended date, and that would be after the range of April 25-May 10 for green beans, sweet corn and tomatoes. These are all considered "tender vegetables."

Melons, peppers, pumpkin and squash are considered "warm-loving" and should be planted in the range from May 10 to June 1. Pumpkins planted for Halloween jack-o'-lanterns should be planted about Father's Day. These pumpkins will get ripe too quickly for use in late October if planted at the normal time. Pumpkins for pies can be planted in the May 10-June 1 period.

Any time now, when soil conditions permit, it is time to plant vegetables such as asparagus crowns, leaf lettuce, onions, peas, potatoes, radishes, rhubarb plants, spinach and turnips. Give it another week or two and it is time to plant broccoli, cabbage and cauliflower. As with most things, a little bit of planning goes a long way in preventing problems later on.

Questions abound regarding fertilizing the garden. The rule-of-thumb rate for fertilizing flower or vegetable gardens (without soil test information) is about 15 pounds of 10-10-10 per 1,000 square feet. If you are using 12-12-12 or 13-13-13 fertilizer, use about 12 pounds per 1,000 square feet.

Soil pH may need to be adjusted due to the addition of lime and sulfur, which are acidifying. Generally, about 4.25 pounds of lime neutralizes the acidity from 1 pound of nitrogen or sulfur. Beware of pH requirements for different plants before you go out to apply lime. Surrounding plants are also affected. Examples would be blueberries, rhododendron, azalea, pin oaks and many evergreens, which are acid-loving plants.

Reminders

• It is about time to mow already, and remove no more than one-third of the leaf blade at a time to prevent raking or catching clippings.

• Cut back butterfly bushes to live material, with a 10-inch maximum height.

• Cut back mums, but leave 2 inches of dead material since much stored food is located there.

• Cut back ornamental grasses to a height of 4 inches or so.

[By JOHN FULTON, University of Illinois Extension]