What to do in the Garden in September and October

Garden Maintenance:

Continue weeding to prevent the seeds from overwintering and give yourself a head start in the spring. If you don’t have time to weed at least cut off and discard the seed heads.

Watering trees and shrubs is as important as watering your perennials. If it’s a dry fall make sure trees and shrubs are well watered until the soil freezes. This is extremely important for anything planted this season.

Mulch newly planted trees and shrubs to prevent heaving in the winter. Keep the mulch at least 4 inches away from the trunk.

Prevent mouse and rabbit damage to thin-barked trees by installing 18 inch to 24 inch high hardware cloth. Cut any grass around the base of trees short to discourage nesting by these critters.

Perennials:

Remove and discard all diseased plant material. Do not place in compost pile as some fungal spores can winter over in ground litter and soil and will reinfect plants next season.

Disinfect your pruner after working on diseased plants before moving to a new plant. A quick spray with Lysol or a dip in a 10% Clorox solution works well.

Remove and destroy iris foliage to eliminate the eggs of the iris borer.

You can leave the seed heads of astilbe, black-eyed-Susan, cone flower, daisy etc. intact to provide food for the birds as well as provide winter interest.

Divide any perennials that have become overgrown, diminished bloom or have formed a “doughnut” shape with a bare spot in the center of the clump. It’s best to transplant early in the fall while there is still enough time for their roots to settle in for the winter.

Bulbs:

Begin planting spring bulbs. You will get better results if you plant when there is a month of 40 degree or above soil temperature (mid Sept. – mid Oct. in our area). This allows the bulbs to set strong roots and will give you better blooming.

Fertilize bulbs when you plant them using compost or 5-10-10. Cover the planting area with 2-3 inches of compost.

With some bulbs it’s difficult to tell the top from the bottom. The skin is loose at the top and attached at the bottom. If you can’t tell, plant them sideways!

To deter moles, voles and squirrels, ring the planting area with a mixture of soil and gravel or put small chicken wire between the bulbs and soil surface.

Plant bulbs 2 to 3 times as deep as their height, a little deeper for naturalizing varieties.

Lawn:

Overseed bare spots in the lawn. Filling in bare spots helps prevent weeds in those areas next year.

September is the best time to fertilize your lawn and seed a new one. A topdressing of good compost is an ideal and natural fertilizer.

Remember to water the grass seeds regularly to keep the soil moist and choose high quality seed appropriate for your site.

In early September check your lawn for grubs by lifting up about a square foot of sod. If there are more than 10-12 grubs per square foot you may want to treat for grubs. First identify what type of grub you have so you know the proper treatment. Contact your Cooperative Extension for help in identification and treatment options.

Keep mowing the lawn. Make the last cutting one inch lower than usual to prevent matting and to discourage snow mold.

Vegetables & Herbs:

Any time after the first frost through late October is a good time to plant garlic.

Pick off the tomato blossoms that won’t have time to develop tomatoes so the nutrients go into the tomatoes already growing on the vine.

Plant cover crops such as peas or clover as you harvest your vegetables. This will reduce the need for weeding and will add nitrogen to the soil.

Another option is to sow a cover crop such as rye or winter wheat in the vegetable garden. Turn it over in the spring.

Wait until the seeds of your sunflowers are firm and done growing. Cut off the sunflower head leaving about one foot of stem. Hang in an airy dry place until ripening is complete.

Dig mature onions on a dry day. Store in a well ventilated place in mesh bags (or even panty hose).

Plant radish, kale, spinach, and lettuce seeds in early September as your last crops.

Pull up your hot pepper plants and hang them until the peppers are dry. (Or thread them on a string to dry.)

Allow nuts to fully mature on the trees. Remove the outer green hull of butternuts and walnuts.

Try potting up some of your garden herbs and bring them in the house for fresh herbs during the winter.

If you had any vegetables with fungal problems make sure that area is cleaned of all plant debris and avoid planting the same variety in the same spot next year.

Miscellaneous:

Dig and store summer blooming bulbs, caladium and elephant’s ears before frost and tuberous begonias, cannas, dahlias after the foliage is blackened by frost.

Bring in tender perennials such as scented geraniums and rosemary and any annuals you want to overwinter BEFORE you have to turn on the furnace. This cuts down on the shock of moving inside.

Make cuttings of plants treated as annuals such as scented geraniums, strobilanthus, impatiens, and coleus.

Collect seeds from open pollinated plants such as Kiss-me-Over-the Garden Gate, Big Max Pumpkin, and Brandywine tomatoes.

If collecting seeds be sure to keep them dry and chilled 35 to 45 degrees Fahrenheit.

Join a seed exchange such as Seed Savers. Contribute extra seeds to organizations such as the American Horticulture Society and the Herb Society of America.

Add color to the autumn garden by planting mums, kale, flowering cabbage, and pansies.

Plant trees and shrubs now. They will have time to develop roots before winter sets in.

Fallen leaves are one of the most wasted natural resources the home gardener has. They can be used as a mulch to improve soil texture and to add nutrients. (Get some from your neighbors as well!)

Small leaves like linden or birch trees can be spread on gardens directly. Larger leaves can be shredded or run over with your lawn mower before spreading. Avoid using black walnut or butternut as they can be toxic to many plants.

Excess leaves can be composted for use next spring. They decompose faster if shredded first

Begin bringing in houseplants that lived outdoors all summer. Wash off with a good spray of soapy water. Check for diseases and insects before bringing inside.

Take pictures of your gardens. Make notes for next year’s gardens now. What worked, what didn’t, what to add, remove, or move.

Begin to get Poinsettias ready for December flowering. They need fourteen hours of total uninterrupted darkness and ten hours of bright light.

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