Ear to the Ground: The Insider Dirt to Gardening in Upstate NY

Almanac: What to do in the Garden in September & October (2016)

by cathym on September 13, 2016

Garden Maintenance

Continue to remove weeds to prevent perennial weeds from having a head start in the spring and to prevent annual weeds from setting seeds. If time constraints prevent digging up weeds, cut off the seed heads before they mature.

Water trees and shrubs to encourage full vigor and hardiness in preparation for the winter ahead.

Add compost to your beds to improve soil texture, promote beneficial microbes, and to prepare the garden for next spring.

Mulch newly planted perennials, trees and shrubs when the soil temperature reaches 50 F to prevent heaving in the winter. Make sure the mulch is not touching tree or shrub trunks. Pile leaves on your macrophyla hydrangeas.

Allow annuals such as nicotiana, annual poppies, cleome, and Verbena boniarensis to drop seeds in the garden.

Prevent mouse and rabbit damage to thin-barked trees and shrubs 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.

Don’t heavily prune trees or shrubs at this time. Severe pruning can disrupt normal dormancy.

Don’t prune your lavender. Wait until spring.



Remove and discard all diseased plant material. Do not place in compost pile as some fungal spores winter over and may re-infect plants next season.

Disinfect your pruner after working on diseased plants before moving to a new plant. A quick spray with Lysol, a dip in a 10% Clorox solution, or using alcohol wipes all work well on your tools.

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

Mound soil around your roses after the temperature drops. Bring in fresh soil to avoid disturbing roots.

Leave the seed heads of astilbe, black-eyed-Susan, coneflower, daisies, intact to provide food for the birds as well as giving winter interest. Also, leave ornamental grasses, red osier dogwood, asters, Russian sage, for winter interest.

Divide any perennials that have become overgrown, exhibit 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 the roots to settle in for the winter. Extra plants can be shared with a friend.



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

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

It’s difficult to tell the top from the bottom of some bulbs. 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, put a layer of pea gravel or small gauge chicken wire between the bulbs and soil surface.



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

September is the best time to seed a new lawn. A top dressing of good compost is an ideal natural fertilizer.

Water the grass seeds regularly to keep the soil moist. 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. Complete your grub control program by the middle of September. Contact your Cooperative Extension for help in grub identification and treatment options.

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

If the leaves aren’t too thick on your lawn leave them and mulch them in when you mow. They feed your soil naturally.


Vegetables & Herbs

Any time after the first frost through late October is a good time to plant garlic. Plant the largest cloves 3 inches deep in loose rich soil.

Pot up some parsley, chives, oregano, or mints to use indoors. You can also freeze or dry herbs for winter use. Wash off the plants to prevent insects from entering your home.

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

Plant cover crops when you harvest your vegetables. This will reduce the need for weeding and will add nitrogen to the soil.

Dig mature onions on a dry day. Store in well ventilated 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.)

If you had any vegetables with fungal problems make sure that area is cleaned of all plant debris and rotate vegetable locations next year.

Mulch strawberry plants.



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 or take cuttings of annuals and tender perennials such as scented geraniums, begonia and rosemary and any annuals you want to overwinter before you have to turn on the furnace.

Take cuttings from annuals such as scented geraniums, begonias, strobilanthus, 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 cool. 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.

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 them off with a good spray of soapy water. Check for diseases and insects before bringing them inside.

Take pictures of your gardens and notes for next year’s gardens now: what worked, what didn’t, what to add, remove, or move. (You think you will remember next year but you probably won’t.)

Let your amaryllis bulbs begin a 2 month rest period.

Lay out thick layers of cardboard or newspaper covered with mulch over areas that will become new beds in the spring. These will smother grasses and weeds as they break down making spring efforts easier.

— Carol Ann Harlos & Lyn Chimera, Erie County Master Gardeners


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