On Gardening/September Garden Tips

9-8-97
University Park, Pa. -- Perennial flowers can be safely moved at this time. Warm soil temperature allows for optimum root growth and establishment before the soil freezes. If you move and divide peonies, make sure to replant them only one and one-half to two inches below ground level. Planting too deep at this time keeps the new plants from blooming. After the soil freezes later this fall, apply a good layer of mulch over all newly moved and divided perennials to keep them from heaving from the soil over winter.

Onions are maturing in September and should be removed from the garden as soon as the tops have dried. Brush any loose soil from the bulb surface. Once they have been removed from the garden store them in a shady, dry place until the tops and outer skin are fully dry. Store over winter in mesh bags to promote air movement.

Wood ashes contain phosphorus, calcium and some potassium. If you still have fireplace or stove ash from last year apply a light dusting on the garden, flower beds or lawn. Be careful not to overdo it, and never apply wood ash to acid-loving plants like azalea or rhododendron. Yearly application rates of about one garden shovel per each 100 square feet of area will not harm the soil. I have seen cases where higher rates have damaged the chemical quality of the soil.

Fall planting season is at its best in September. Commercially dug or produced plants should be set as soon as possible to allow time for good root growth this fall. If you are planning to move plants around on your property, needle or cone-bearing evergreens can be moved now. Make certain you have a good sized root ball on the plants to assure establishment. It is best to wait until the leaves begin to drop from deciduous plants before you attempt to move them. A good root ball is also important here too.

Spring flowering bulbs have always been planted at this time of year. Bulb packages provide all the directions a gardener will need to assure proper planting technique.

However, what the package fails to suggest is planting design. I try to encourage mass plantings of one flower type. The use of several dozen bulbs in one spot will produce a better effect than a mixture of many colors. European gardens often contain several thousand bulbs of a single type to create a display that is impossible to describe.

Weed control is an important aspect of September gardening. Just as the garden crops begin to mature, so do the weeds. At this time of year it is important to keep the garden weed-free, or at best prevent weeds from setting seed. A single weed pulled now can prevent hundreds or even thousands next spring. It is also a known fact that some weeds harbor insect and disease problems that can attack next season's garden.

Perennial weeds should also be controlled at this time. Remember these live over winter and will return as soon as conditions warm next spring. Check at your local garden center to determine if herbicides are available for your particular weed problem. Read the label carefully to determine if both the crop and weed is cleared for safe treatment.

House plants that have been enjoying the outdoors all summer should be taken back inside before temperatures drop below 50 degrees F. Many of our tropical house plants can be injured by cool temperature or killed by even a light frost. Inspect these plants for insect pests before you take them back indoors.

***

**Dr. Robert Nuss is a horticulturist at Penn State. He coordinates all extension horticulture programs. He has bachelor's, master's, and doctoral degrees in ornamental horticulture and has been on the Penn State faculty since 1966.