Autumn in the Vegetable Garden

It's tempting to leave our summer tomatoes, cucumbers and squash in the ground, giving up on our vegetable garden after Labor Day, but fall is the prime time to work on our vegetable garden, getting the most out of the growing season by adding cool season crops.

       There are a few tasks that are best done before the beds are cleared, and the first is to document the good, the bad and the ugly from our summer garden. Walk around the garden taking notes, drawing pictures and photographing to document challenges and successes, problems, tasks and ideas for next year. Mapping the planting plan helps a vegetable gardener maintain a healthy crop rotation when things look different in the spring. Think through which plants grew well and should be repeated in next year’s garden. It’s good to note planting dates and seed sources, spacing, beneficial combinations, harvest dates and productivity.

       Autumn is time to bring in twigs, nuts, berries and seed heads to dry for fall decorations or winter wreath-making. Gather stems into bunches, secure with rubber bands and hang them to dry. Harvest herbs to dry, freeze or use fresh. If there are warm season crops in the garden that performed particularly well, it’s possible to harvest the mature vegetables and save the seeds. Those from heirloom, open-pollinated tomatoes, beans and lettuce can be saved, dried and stored for next year’s garden.

       Only then should beds be cleared by removing debris, leaves, clippings, fallen fruit and tired summer vegetable plants; this mindful garden sanitation removes the overwintering habit for many insects. Cucumber beetles and squash bugs overwinter on leaf litter and create problems in the spring. Space is then created to tuck in cool season plants that successively produce up until the first frost. Take advantage of the cooler weather when weeds are slowing down and moisture is plentiful, making maintenance easier.

       There are a couple of considerations for planting fall vegetables, and most importantly is timing. Chicago is on average, frost-free from mid-April until the third week in October. We anticipate the first frost around October 15 in the suburbs and a bit later in the city. Vegetable varieties have differing tolerances to frost and vary in the number of days they need to fully mature. When allowing plants to mature while there is enough sunlight and warmth, the timing must be calculated by counting back from the frost date.

       A general indicator for the ideal time to plant cool season crops is when the first warm season crops are slowed by disease or peter out. Slow-growing early cabbage, broccoli, kale and collards should be transplanted into the garden in mid-August, 60 to 70 days before frost arrives. It’s important to note which plants are slower starters versus those that grow quickly by checking the days to maturity printed on the seed packet. Subtract that number, plus a few days for germination, from the frost date to find the start date.

       Cool weather brings out the sweetness in vegetables, particularly root crops. Beets are frost-tolerant and mature in 60 days, while radishes can take a hard freeze and are ready in just 30 days. Carrots can be directly sown for a fall crop of sweet crisp roots in 60 to 70 days and harvested as baby carrots if a hard frost comes early. Asian greens, mustards, tatsoi and mizuna can be sown with only 45 days to frost.

       Fall is also a great time for success with salad plants. Lettuce grown for baby greens can be planted well into September. Red varieties ‘Red Rosie’ and ‘Red Salad Bowl’ are a bit more tolerant to temperature extremes, as are the buttercrunch varieties. Arugula and spinach are plants that are adapted to mature in cooler temperatures and can take a hard freeze. Plantings made two weeks apart stagger and extend the harvest.

       Season-extending techniques allow gardeners to cover and protect tender vegetables from being damaged by the first frosts of fall. It’s even possible to extend the growing season of hardy crops by protecting against a season-ending hard frost. Row covers, garden blankets or light Agribon floating row cover cloth (available online) thrown over small hoops or raised beds will extend the season to eke out a few more harvests.

       One of the last planting tasks in the autumn vegetable garden is the sowing of edible bulbs. Garlic, shallot and onion sets should be planted by Halloween for overwintering and harvest next year. In Chicago, hardneck garlic varieties are best purchased directly from a garden center or certified seed source. ‘Music’ and ‘German Extra Hardy’ are varieties that grow well. Divide heads into individual cloves with the papery wrapper still attached and plant them two-to-three-inches deep in rows a foot apart.

       Reveling in the garden successes of summer reminds us that fall and winter gardens are our link to spring.

Lisa Hilgenberg is the horticulturist at the Regenstein Fruit and Vegetable Garden in the Chicago Botanic Garden, located at 1000 Lake Cook Rd., in Glencoe. For more information, call 847-835-5440 or visit ChicagoBotanic.org.

 

Planning a 2017 Garden

A new class, Vegetable Gardening, taught by Lisa Hilgenberg, will be offered from 9 to 11 a.m.,
January 21, with Planning Your Vegetable Garden for Seed Saving from 1 to 3 p.m. ChicagoBotanic.org has details.