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Cool Season Vegetables to Grow in Allentown

Updated: Aug 21, 2022


It’s time to get planting those cool-season vegetables for fall. Start on your fall crop of veggies soon, and grow them even longer and healthier with a few tips to extend your growing season.

Extend Your Garden Season

While our first frost in Allentown might happen anywhere from late September to late October, you may want to offer your fall veggies a little extra protection. Covering your plants helps to trap warm air around your plants, warm the soil, and retain some humidity. Here are a few different options for covering your plants that can extend your growing season by up to a month:

Cloches are individual plant covers, usually made of clear or slightly opaque plastic, with a vent hole for air circulation. They’re great for individual plants like cabbage, kale, lettuce, broccoli, or cauliflower. Cloches can be put on your plants for frosty nights and removed during the day. Once the frosty mornings are lasting longer and the day time temps are staying low, you may want to leave cloches on all day long. Row covers are a better option for veggies like carrots, beets, onions, and radishes. Some people use very light mesh fabric in the summer to prevent butterflies from getting to cabbage and other brassicas. Summer row covers can be draped right over the veggies, but you’ll want a little more support in the fall because you’ll need heavier fabric for extra protection. Row covers with hoop support are the best kind to get for frost protection. This way, you’ll be able to drape a heavier fabric over them on frosty nights. Garden fabric will keep your plants protected from the cold, but you will need to remove it during the day so they can still get light.


Cold frames are a sturdier option, usually consisting of a wooden frame with a glass or Plexi window on top to let light in. Some people build permanent ones that they plant straight into. You’ll need to prop the windows open for air circulation during the day. Cold frames with good sun exposure and protection from the wind can extend your season well past an extra month. Greenhouses are the ultimate season extender, but they’re a significant investment. If you’ve got one, make the most of it by gardening as long as possible.

Rotating Crops & Cover Crops for Better Soil

Rotating your crops is a pretty easy way to discourage pest infestations, and give your plants access to more nutrients. Different types of plants use different nutrients, and some plants even add nutrients back into the soil. Draw a diagram of what you planted and where you planted it when you’re finished planting in the spring and fall. Next year, consult that diagram to make sure you are rotating different plant families into each garden space.


Crop rotation can get really complex, and if you have a large garden, you may want to get into some detailed planning. Managing a small scale garden can get bit tricky too, here is a simplified version for small gardens: One plot, row, or raised garden bed, should be rotated in this order: Year 1: Fruiting Crops (tomatoes, peppers, eggplant, squash, cucumbers), followed by a cover crop in the fall. Year 2: Leafy crops (lettuce, spinach, broccoli, Brussels sprouts, cauliflower, cabbage) Year 3: Root crops (carrots, turnips, parsnips, potatoes)

In year 4, you can start over with fruiting crops in that space again. You can also plant a cover crop every fall if you like because they help improve your soil and control weeds. Good cover crops for Pennsylvania include buckwheat, cowpeas, oats, and winter rye. Cover crops should be planted in the fall, and most can be planted well into September and still be effective. You want them to germinate and start to grow, but you don’t want them to flower. If they begin to flower, you’ll need to mow them down. You can just leave the mown crop lying on the garden all winter and till it under in the spring to enrich the soil. If you’ve never used a cover crop before, oats are a good one to start with because they usually winter kill here, so you don’t need to worry about them coming up again in the spring.


Add Some Color

The garden can start to look a little drab and lackluster in the fall, so intersperse your veggies by planting cool-season flowers or grasses. Chrysanthemums are a fall classic, but plants like asters, pansies, ornamental kale, fountain grass, alyssums, black-eyed Susans, and dianthus will keep your garden pretty and colorful for many more weeks.

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