Al Krismer Plant Farm


September Garden Tips

from Al Krismer Plant Farm

Dear Gardening Enthusiast,

But now in September the garden has cooled, and with it
my possessiveness. The sun warms my back instead of
beating on my head ... The harvest has dwindled, and I
have grown apart from the intense midsummer
relationship that brought it on."
- Robert Finch

With the arrival of September, we begin the transition from summer to early fall with a jolt of cool nights and shorter, sunny days. Now is the time to revive the lawn, tuck spring-flowering bulbs into the sun-warmed soil, and line the front walk with a riot of chrysanthemums.

Check  our September  recipes

Annuals and Bulbs
  • As you select your flowering bulbs to plant this fall, keep in mind that larger caliber bulbs give big, showy displays, but cost more. Tulip bulbs should be 12cm and larger since smaller bulbs might not bloom next spring. Smaller caliber bulbs usually are less expensive, with a smaller show, but are great for brightening nooks and crannies in your yard
  • As you plant your spring bulbs, remember that a mass planting of one flower type or color will produce a better effect than a mixture of many colors. Flowers of bulbs stand out more vividly if displayed against a contrasting background. For example, white hyacinths among English ivy, yellow daffodils against a 'Blue Girl ' holly hedge, or red tulips towering over a carpet of yellow pansies
  • Perennials, especially spring bloomers, can be divided now. Enrich the soil with peat moss or compost before replanting.
  • Plant mums in pots or in the ground to add color to your fall garden. Mums need a spot where they will get at least half a day of direct sun, preferably more. Most people use them as annuals because it takes some work to get full bushy plants that look as good the second year as they did when you bought them. However, if you want to treat them as perennials, be sure to get our fact sheet on chrysanthemum care.
  • Root cuttings from annual bedding plants such as begonias, coleus, geraniums and impatiens. These plants can be overwintered in a sunny window and provide plants for next year's garden Click here for more info
  • Tuberous begonias and gladioli are usually past their best by the end of September, so before any hard frost they should be lifted and stored in a dark frost-free area. Before storing they should be dusted with a suitable fungicide to prevent rotting. Also make sure that they are totally dry before storage.

Vegetable and Herbs:

  • Harvest crops such as tomatoes, peppers, eggplants, melons and sweet potatoes before the first frost, or cover the plants with blankets, newspaper, etc., (but not plastic) to protect them from light frost.
  • After harvest, avoid storing apples or onions with potatoes or carrots. The ethylene gas given off by the apples and onions will cause potatoes to sprout, and the carrots will taste awful.
  • Herbs such as parsley, rosemary, chives, thyme and marjoram can be dug from the garden and placed in pots now for growing indoors this winter.
  • Sowing seeds of radish, lettuce, spinach and other greens in a cold frame will prolong fall harvests.
  • Mix lettuce ‘Black Seeded Simpson’ and lettuce ‘Red Sails’ and seed empty areas in your flower and veggie gardens for a colorful and edible living mulch. Rake the soil to a depth of 2 inches and seed. Water lightly and keep moist. Seed will germinate in 3 to 4 days.
    Click here for more fall lettuce information
  • Hot peppers will keep best if stored after they are dry. Thread the peppers on a string to dry. Hang in a cool, dry place.

    Click here for planning the fall vegetable garden

Garden Maintenance:

  • Dig new garden beds for next spring. Incorporate plenty of organic matter, such as leaves, and leave the soil rough to allow good water penetration. Freezing and thawing will break up heavy clay soils. Plant a cover crop, also called a green manure, to increase the soil's organic matter content.
  • Dig tender bulbs, such as cannas, caladiums, tuberous begonias and gladiolus, before frost. Allow to air dry, and store in dry peat moss or vermiculite
  • Get your tools, especially your mower, ready for the off-season with a little simple maintenance. They'll be ready to go to work next year when spring fever strikes.
  • Clean up debris in the lawn and garden. Leaves, sticks, rocks and other late season leftovers can harm next year's lawn and harbor pests and diseases over the winter.
  • Allow plants to finish the summer growth cycle in a normal manner. Never encourage growth with heavy applications of fertilizer or excessive pruning at this time. Plants will delay their dormancy process that has already begun in anticipation of winter in the months ahead. New growth can be injured by an early freeze
  • Do not wait for frost warnings to move your plants indoors. Temperatures of 45 degrees Fahrenheit or lower can damage many tropical house plants.
  • The end of summer is a good time to examine your garden critically and plan for next year--while your triumphs and disappointments are still fresh in your mind. Take pictures, make notes. Which combinations worked? Which didn't work so well?
  • To prevent damage to bulbs from moles tunneling in your flower beds, treat the soil with an insecticide to kill the grubs. To avoid damage from mice or other vegetarian rodents, plant the bulbs in cans. Cut both ends from large fruit-drink cans. Bury the cans to their rims. Fill about one-third full of soil, place one bulb in each, and cover to the surface with soil

Shrubs and Trees:

  • Mid-September through mid-October is a great time to plant or transplant trees and shrubs. Plants moved or planted new now will have up to two months to settle in and spread their roots before they go dormant. Prepare a hole twice the diameter of the root ball but at the same depth and water thoroughly. Mulching will help protect against large fluctuations in soil temperature and moisture. Be sure to stake or guy-wire tall plants to protect them from strong winds. Click here for more information
  • Do not prune azaleas, rhododendrons and other spring flowering shrubs because they have already set their buds for next year's blooms. If you feel these shrubs do need to be pruned, however, you can prune them now, but you will sacrifice next spring flowers
  • As the weather cools, begin watering established trees and shrubs less often, giving them time to harden off for winter, but continue to water evergreens until the ground freezes hard. Evergreens continue to lose moisture through their needles throughout winter and must have adequate water in their root zones to avoid winter burn or desiccated needles
  • Seasonal loss of inner needles on conifers is normal at this time. It may be especially noticeable on pines.
  • Remember that roses require special care in the fall. In early fall, suspend fertilization. Continuing to fertilize causes new growth that could be killed by winter's cold. After foliage drops, spray with fungicide, then cover plants with a minimum of 8" of loose, well-drained soil, mulch or compost. Prune canes back to 36" to prevent damage from winter winds.
  • Stop deadheading your roses now. When the blooms wither you can pluck the petals to keep the bush looking neat. Leaving the dead buds on the bush signals it to make seeds (rose hips) and to start hardening off for winter. If you wish to feed them just use a very dilute water soluble fertilizer (half strength or less) and spray it on the leaves for a foliar feed, but don't continue this much longer than past the middle of September.
  • Select accent plants for your landscape that will provide autumn colors. Trees that have red fall color are flowering dogwood, red maple, sugar maple, Norway maple, red oak and scarlet oak. Shrubs with red fall foliage include sumac, viburnum, winged euonymus and barberry.
  • Prune oak trees in the dormant season so as not to increase the risk of oak wilt. Pruning from September to early March is recommended because pruning during the growing season attracts bark beetles, which transmit the oak wilt fungus. Oak wilt is a potential threat in the Midwest and can kill mature oaks in one season

Lawn Care:

  • Early autumn is the best time of the year for the sowing of grass seed. Grass sown in spring is often killed by hot, dry, summer weather. For more vigorous growth, spread a very thin mulch of clean straw over newly seeded areas. The straw shades delicate seedlings from the hot sun and helps preserve moisture in the soil, yet lets enough light through for germination. By the time cold weather arrives, the grass is fairly well established and ready to grow and thicken early the following spring

    Check out video on lawn renovation

  • It is time to apply herbicides to your lawn for winter annual or perennial weeds that germinate or form rosettes in turf during the fall. Check herbicide labels before using, and select an appropriate chemical for the weed types and lawn type in your yard.
  • Don't allow leaves to accumulate on the lawn. Rake them up regularly, and store in a pile for use as mulch in your garden next summer. If leaves accumulate on your lawn and become matted down by rain, they may kill the grass.

House Plants:

  • Poinsettias saved from last year can be reflowered for this year's holiday by placing them in total uninterrupted darkness for 15 hours a day, starting the last week of September and continuing through Thanksgiving. Do NOT leave the plants in darkness all day!

    Click here for helpful info on poinsettia care
  • Move houseplants indoors before nighttime temperatures are consistently in the 50's. Begin readying houseplants for winter indoors. Prune back rampant growth and protruding roots. Check for pests and treat if necessary. Houseplants should be brought indoors at least one month before the heat is normally turned on.
  • Start taking cuttings of your annual plants to bring indoors and carry through the winter. Geranium, coleus, fuchsia, and other plants do best when stem cuttings are rooted and kept in pots indoors through the winter. Be sure to place pots where they receive plenty of light
  • Thanksgiving (or Christmas) cactus can be forced into bloom for the Thanksgiving holidays. Provide 15 hours of complete darkness each day, for instance, from 5 p.m. to 8 a.m., for approximately eight weeks. Keep temperature at about 60 to 65 F. Temperatures of 55 F will cause flower buds to set without dark treatment.

    Click here for Christmas cactus care sheet

    Click here for info on  general houseplant care


Water Gardens

  • The quantity of debris that makes its way into your pond increases during autumn, placing extra burden on pumps, filters, skimmer filters, and other equipment. Remove excess organic materials such as leaves on a regular basis to prevent accumulation
  • If you have trouble with floating fish food or floating plants being pulled into the skimmer try using a fish feeder ring to contain the food or plants.
  • Keep falling leaves and twigs out of the pond to prevent injury to the fish. Prevention is also easier than having to clean the entire pool in the fall. Netting stretched across the pool is an easy preventative to catch leaves or use a skimmer to remove leaves on a regular basis.
  • Reduce your fish feeding. As your water temperature drops below 65? the metabolism of your fish slows down. Start feeding your fish just a couple of times a week. A fish food that is specially formulated for the fall (wheat based) is “a must” at this time of the year. Stop feeding your fish completely when water temperatures fall below 55 °. If you don’t have a thermometer for your pond, get one
  • Trim your perennial aquatic plants that begin going dormant as the weather cools. Your aquatic plants aren’t dying, but they may turn yellow or brown as they go dormant. You should trim back the yellowing leaves to prevent the fall out debris from building in your pond.

    For more fall water gardening tips click here


Insect and Disease Control

  • Fall webworm caterpillars have been covering shade trees with webs throughout much of Ohio. These caterpillars are fuzzy, with black dots on their backs and can extend to about 1 1/2" by the time they complete their development.

    For more info click here

  • If your iris leaves are flopping, you may have iris borers. Moths lay eggs on the leaves in the spring. When the eggs hatch, the larvae move down the foliage and bore in the fleshy root, eating it and rotting it out. Dig up plants, cut out the larvae and damaged roots. Replant healthy roots. Do not mulch irises. Consider spraying next spring with an insecticide to prevent borers next year.
  • Slug time again! Clean up debris, old pots and places they can hide. With a lack of rain, the heavy dews bring them out to feast. Controlling slugs now, during their breeding season, should result in fewer next year

    Click here for Ohio State Extension Fact Sheet on controlling slugs and other insects

    Click here for article on controlling pests in the vegetable garden


Garden Critters

  • To reduce nuisance wildlife problems, seal off places wildlife can enter like chimneys and under porches. The Wildlife Conflicts Information Hotline (1-800-893-4116) is an excellent resource.
  • Continue attracting insect eating birds to the garden area by providing them with a fresh water source.
  • With cooler temperatures, uninvited guests may make their way into your home. Many home maintenance practices done now will winterize the house and help prevent insect entry
  • Skunks, raccoons and other animals are attracted to grubs and may tear up lawns in search of them.
    For more info on controlling these pests  click here

  • Animals such as chipmunks, ground squirrels and voles like to feast on bulbs. Deter them by planting daffodils, squills, grape hyacinths and crown imperial bulbs; such plants are known to have a taste these animals dislike. The crown imperial has a horrible smell, and below-ground diners are known to avoid it. Interplant crown imperials among tulips and other "tasty" bulbs.
  • Leave seed heads on your black-eyed susans; they're a great food source for goldfinches



Monthly Garden Tips are sent out by Al Krismer Plant Farm during the year. Look for the Tips and the expanded e-news before the 10th of the month. Quick Links below

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