Season Extenders and Growing Fall Vegetables

Although fall might be the start of the end of the gardening year, it doesn’t have to be. Gardeners who want to extend the vegetable gardening season have several options for growing fall (cool season) vegetables.

It is important to remember that the best time to test your garden soil is in the fall. Tests conducted in the fall will provide the information needed to modify the soil as necessary before winter. Applying soil amendments in the fall will help get your garden ready for spring.

To know when to start your Fall gardening activities, you must first know the date of the first frost or freeze. The average frost/freeze dates in your area can be determined by your zip code. To find out when the first and last frost/freeze is in your area, go to an online tool and enter your zip code. The zip code for Penn State’s main campus at University Park, PA is 16802 and the frost/freeze dates are October 12 – May 10. This means that the growing season is about 155 days long.

This article discusses two topics related to Fall gardening: season extenders and growing fall vegetable crops.

Season Extenders

A season extender is a device that helps gardeners to grow vegetables outside of the usual growing season. This means that they can grow vegetables before the first frost date, or after the last frost date. Growing vegetables during the times that are not the normal growing season is often called growing on the “shoulders” of the season. A gardener should consider how much time, money, and effort they are willing to spend on season extenders before deciding which type(s) to use.

Low Tunnels

Low tunnels are an easy and effective way to extend your growing season. The hoops create a structure that will protect the plants from insects, physical damage, as well as low temperatures.

Low tunnels are made up of three things: the stuff to build the tunnel (fabric or plastic), the galvanized steel wires to support the fabric or plastic covering (PVC and bamboo can also be used for these supports), and a sandbag or something similar and heavy to hold the covering tight and in place. How long the hoop will last will depend on what it’s made of, the weather, and how often it’s used.

The size of hoops used in gardening varies depending on how much room the mature vegetables will need. There are hoops of various sizes available for purchase. The size of the hoops and the heights and widths of the hoops can vary depending on the type of crops being grown. Gardeners can also create their own custom sizes to match their garden plan.

To secure the hoops, place them over the center of the crop row about 3 to 4 feet apart. You can secure the fabric or poly by placing a sandbag by the side of each hoop. Instead of staking the hoop covering down, you can bury the edge of it a few inches in the soil.

The tunnels can be covered with a fabric row covering in the fall and spring. As the temperature outside drops, the fabric that is covering the outside of the building may be replaced with a 4mm to 6mm poly. When you are not using the low tunnels, take them down from the garden along with the coverings. The hoops should be cleaned and stored in a safe place until they are needed again. Check to make sure that the hoops holding up the covers are still in place, and that the covers haven’t blown away. Replace any damaged fabric or poly row covers, and check that the hoops holding up the covers are still in place and that the covers haven’t blown away. If either of the coverings have holes in them, it could result in heat escaping from the tunnel. Insects could also get in through the holes, so it’s best to replace the coverings when they start to develop holes or openings.

Cold frames and hotbeds

Cold frames and hot beds are used to grow cool-season crops in the fall and spring. In the fall, you can sow seeds directly into the ground in either beds or containers. You can also grow seedlings in flats in the beds. A cold frame only uses sunlight to regulate the temperature inside, while a hotbed uses an electric heat mat or another heat source from outside. In some cases, manure may provide a source of heat.

The main purpose of using a season extender is to provide a protected environment for cool-season plants to grow and survive through the winter. A cold frame is a type of garden structure that is used to protect plants from cold weather. A hot bed is a type of garden bed that is heated by the sun’s rays. The bed covering can be made of materials like glass, plastic, fiberglass, etc. Some designs have the bed covering installed at an angle so it can capture more sunlight. The angular design of this solar panel is helpful in capturing the sun’s heat, but it is not necessary.

Take care when setting up the frame or bed. The best location for a garden is on a slope (to help with drainage), with the sun shining on it from the south or southeast. This allows for maximum sun absorption. The back of the box should be placed next to a wall or hedge to protect the plants from cold winds and winter precipitation. It is not necessary, but if you want to keep the heat captured in the bed, it is helpful to protect it from cold winds, ice, and snow.

Cloches

Traditionally, cloches were glass, bell-shaped coverings placed over individual plants in order to protect them from the cold weather.

The term “cloche” has come to mean any individual covering made from plastic. The term “cloche” includes movable, multi-plant coverings. The coverings can be moved and are made of different materials like wood, fabric, etc. The goal of building a cold frame is to create a space that will protect plants from cold temperatures, brisk winds, and damaging insects.

Growing Fall Vegetables

Warm-season and cool-season vegetables defined.

There are two types of vegetables, warm-season and cool-season. A vegetable that thrives in warm weather completes its life cycle in one growing season. You can plant warm-season vegetables when the soil has warmed up or, in some cases, you can plant them directly in the soil. Some vegetables that are typically harvested during warm weather months are tomatoes, eggplants, beans, cucumbers, peppers, sweet potatoes, watermelon, and summer squash.

A vegetable that grows in cooler temperatures needs cooler temperatures to germinate and set seed. The term cool-season vegetables refers to vegetables that are the first to be planted in the spring and may also be planted later into the season. Some of the best crops to grow in the fall and extend the season are leafy greens and root crops. Some common cool-season vegetables are Asian greens, asparagus, beets, broccoli, Brussels sprouts, chives, cabbage, carrots, cauliflower, Swiss chard, kale, leek, lettuce, onion, parsnips, peas, radishes, spinach, and turnips.

While cool-season crops can technically grow in warmer temperatures, the heat will degraded the quality of the harvest. This is a good example of a radish that has been left in the soil for too long. The radish will become tough, and spicy and will also flower prematurely. The process of bolting or “going to seed” is caused by a change in temperature and/or day length.

Endive Plant: Cool-Weather Greens

Did you know that endive comes from the same family as the daisy? If you ever let your endive plants flower, you will understand how they got their name. There are two varieties of endive – escarole endive (Cichorium endivia var. latifolia) and curly endive (Cichorium endivia var crispum). Belgian endive and radicchio are types of plants that are in the Cichorium genus, but they are not from the endivia species. Even though they are often referred to as “endive,” this is not accurate. It’s easy to see how this can be confusing. There are several different types of endive, including endive, escarole, frisee, curly endive, and endive lettuce.

It is thought that endive comes from Europe and Asia where it is still a popular vegetable. Curly leaved plants have narrow leaves with deep cuts that grow in a large central rosette. The leaves are light green in the center and dark green at the edges. The darker the leaf the more bitter the flavor. Different types of frisee, including red varieties, can add contrast and visual interest to a salad.

Escarole endive is a type of leafy vegetable that has wide, smooth leaves. It’s a fairly hardy plant that does well in cooler weather. The endives that are less bitter in flavor are the ones that can be used in salads, similar to frisee. The outer leaves of chard are slightly tougher and perfect for cooking like other leafy greens, or chopped and used in soups.

If plants are left to mature, they will grow a tall stalk with blue flowers that resemble daisies. Endive seeds are small and light brown, and they come in a little paper capsule. They’re easy to collect, and they will readily self-seed.

The tap root of all endive plants, containing a milky liquid, is main edible part, though it can be slightly toxic when fresh. Drying and grinding roots to make a chicory coffee alternative is a common practice. C. intybus Magdeburg and Brunswick are the best varieties to use for the coffee substitute.

Some growers whiten endive plants to create lighter-colored, less bitter leaves. To blanch leeks, you can either place a pot over the top of the plant or secure the leafy heads together with a rubber band or string to block the light from the center of the plant. This should be done a few weeks before harvest, and the blanched plants should be used as soon as possible to avoid them going to seed.

Planting Endive

Endive should be planted during the cooler months as it is a cool weather vegetable. You should sow the seeds in early spring if you want to harvest them up to early summer. You should sow them again in mid to late summer if you want to harvest them into winter. Endive should be sowed in early fall in warmer climates so that it can be harvested from fall to the following spring.

Seeds should be started indoors 6-8 weeks before the last frost date. They can be transplanted outside after the last frost when air temperatures are stable. If the temperature fluctuates by going up or down, this can cause plants to bolt.

Sow seeds in mid to late spring in 18 inch apart rows and thin to 7 to 8 inches apart. Don’t let the thinnings go to waste! These young leaves are perfect for salads. For this plant to thrive, it needs to be in an area that gets full sun to part shade and the soil needs to be well-drained and constantly moist.

If you’re looking for a type of salad leaf to grow in a large container, Curly and escarole endive are perfect. They work well as a cut-and-come-again type of salad leaf. We carry several options in our shop that will help you have a better gardening experience. Water containers often to keep plants from drying out and going to seed.

Care

Sun and Temperature

Endive needs a minimum of 4 hours of direct sunlight to grow, so it does best in full sun to part shade. Endive grows best in temperatures around 60ºF (15ºC). Plants will bolt if there is too much fluctuation in temperature, so it is best to sow them later in spring when the temperature is more stable. Bolting causes leaves to become bitter and unpalatable. Escarole endive can withstand colder temperatures better than curly varieties and is a better option to grow for fall/early winter harvests. However, it will still need some frost protection, such as a frost blanket. Leaves of escarole varieties will become bitter if exposed to prolonged high temperatures, so it is best to grow curly types during the summer. USDA zones to grow endive are 4-9.

Water and Humidity

To prevent plants from becoming stressed and bolting, it is important to keep the soil moist in the planting beds. The soil should be checked for moisture levels regularly, and watering should be done as necessary. The coolest part of the day is the best time for plants to absorb moisture. It is best to water your plants using soaker hoses or watering cans, so that the water goes directly to the soil and not the leaves.

Soil

Light, fertile, well-drained soil is best to grow endive. Except for heavy clay soils, most types are fine for endive. Heavy clay soils can cause water logging, which rots endive roots and leaves. Loose soil is best. Adding well-rotted manure or aged compost to the soil before planting helps retain moisture while providing nutrients for plants. Endive prefers its pH to be slightly acidic, with a pH of 5 to 6.8.

Fertilizing

Endives will benefit from fertilizer applied throughout the growing season, either by digging in some fish emulsion, blood meal, bone meal, or well-rotted manure a few weeks before planting, or using a balanced liquid general fertilizer once or twice a month during the growing season.

Pruning

Pruning endive is not difficult or time-consuming—you only need to trim back unhealthy plants and remove any leaves that you want to harvest. If you want to have a continuous supply of endive, then you should harvest it frequently to encourage new growth. Clear away any dead leaves or other debris from around your plants, as well as any damaged or sick-looking outer leaves. This will stop fungus from developing in the soil, and it will also discourage slugs and snails. To prevent self-seeding, remove the entire plant at the soil level after it bolts.

Propagation

Start endive seeds indoors in module trays 6-8 weeks before the last frost date. Transplant them outdoors in mid to late spring when daily temperatures are more consistent. Hardening them off slowly means getting them used to the new environment before planting them into the final growing positions.

Alternatively, sow seeds directly into the ground from mid to late spring when it is warm enough for the seeds to germinate. Seeds will not germinate when soil temperatures exceed 80°F. Sow thinly ½ inch deep (1cm).