In climates with four distinct seasons, common sense suggests that most planting should be done in spring.

However, fall has some advantages as a time to plant, and some plants are biologically designed to be planted before cold winter winds blow in Pennsylvania.

Trees, shrubs, hardy perennials: Container-grown plants in this category can be planted from early to mid-fall.

You should plant early enough in the fall for the root system to establish itself. Plan on at least six weeks before the first frost.

Before winter sets in, check weekly and water if dry.

A thick layer of mulch will keep them from heaving out of the ground during periods of freezing and thawing.

An advantage to planting woody plants and perennials in the fall is that they are often on sale at nurseries.

Make sure they are not pot-bound from growing in a container all summer.

Pot bound plants may appear dry because the water has no area to soak in and may have roots growing out of the bottom of the container.

For container-grown plants, loosen the roots before planting.

In the case of trees and shrubs, cut an “X” in the bottom of the root ball and several shallow slits on the sides of the roots to allow them to spread out into the backfilled soil.

Lawns: Most of the turf grass grown in Pennsylvania lawns is “cool season,” including Kentucky bluegrass, perennial rye grass, and fine fescues.

Because these grasses grow best in cool weather, late summer to early fall is an ideal time to plant a new lawn, patch bare areas, or over seed an existing lawn.

Grass seed must receive regular irrigation, especially until it begins to germinate.

This will likely happen naturally in fall rather than spring, when the new grass must withstand hot summer days.

When purchasing, you may find grass seed embedded in what looks like dryer lint.

The premise is that this will hold water when the seed is planted and watered.

Though this may seem like a good idea, the best practice for getting grass seed to sprout is by making sure it has good contact with the soil.

This can be done by loosening the top of the soil before planting or raking in the seed.

Newly planted seed may be mulched with a light layer of straw.

Cover crops: If you have an area where you grow warm-season vegetables or annuals that you normally fallow in winter, you can improve the soil during the winter season by growing a grain or legume.

Cover crops retain nutrients in the soil and legumes fix nitrogen in the soil.

They also help keep the soil from eroding and alleviate compaction.

Cover crops that can be planted in fall include alfalfa, crimson clover, barley, oats, winter rye, winter wheat and hairy vetch.

Cover crops can be planted between the last of your warm-season vegetables to give them a head start before the weather cools.

If you wait until the end of September or early October to plant a cover crop, winter rye is probably the best choice.

Bulbs: Bulbs such as hyacinths, daffodils and tulips are programmed to grow foliage and bloom after an extended cold period.

They should be planted when the weather is cool in the fall and before the first hard frost.

Fall planting is for the patient gardener.

The reward in spring will be well worth it.

“Growing Green” is contributed by Lehigh County Extension Office Staff and Master Gardeners. Information: Lehigh County Extension Office, 610-391-9840; Northampton County Extension Office, 610-813-6613