How to Harden Off Plants
Acclimating and Preparing Seedlings for Transplant by Hardening Them Off
By Marie Iannotti, About.com
There are 3 approaches to hardening off:
1. Gradually Longer periods of Time Outdoors
2. Place in a Cold Frame
3. Withholding Water
Gradually Longer periods of Time Outdoors
1. Begin 7 - 10 days before your transplant date.
2. Place plants in a sheltered, shady spot outdoors. Under a tree or even on your back porch is fine.
Leave them for 3-4 hours and gradually increase the time spent outside by 1-2 hours per day.
3. Bring plants back indoors each night.
4. After 2-3 days, move the plants from their shady spot into morning sun, return them to the shade in
5. After 7 days, the plants should be able to handle sun all day and stay out at night, if temperatures
stay around 50 degrees F. Keep an eye out that the soil doesn't dry and bake the plants, if the
weather is warm.
6. After 7 -10 days your plants are ready to transplant. Try to do so on a cloudy day and be sure to
water well after planting.
Place in a Cold Frame
1. Begin 7 - 10 days before your transplant date.
2. Indoor grown plants can be moved and left in a cold frame, for hardening off.
3. Turn off heating cables and/or open the cold frame cover for gradually longer periods of time. Start
with 3-4 hours and gradually increase the exposure time by 1-2 hours per day.
4. Close the cover and resume heating at night, if temperatures dip below about 40 degrees F.
5. Plants should be ready to transplant in 7 - 10 days. Try to do so on a cloudy day and be sure to
water well after planting.
Allowing seedlings to wilt has the same effect as gradually exposing them to the elements.
1. Starting about 2 weeks before your transplant date, don't water your seedlings until they start to
2. At this point, water normally, then wait for them to wilt again.
3. After 2 weeks of this process, seedlings should be ready to transplant. Try to do so on a cloudy day
and be sure to water well after planting.
· The moving in and out process can be made easier by putting your plants on a wagon or wheelbarrow and simply wheeling them into the garage for the night.
Non-toxic and Homemade Remedies
Homemade remedies are inexpensive and, best of all, you know what is going into your garden. Many homemade sprays have been used with good results to control harmful insects. They usually involve noxious (but non-toxic) ingredients such as garlic,
cayenne, stinging nettles or horsetail which are diluted in water and blended to be sprayed on the plants. Here are a few simple formulas:
Soft-bodied insects (mites, aphids, mealybugs): Mix one tablespoon canola oil and a few drops of Ivory soap into a quart of water. Shake well and pour into a spray bottle. Spray plant from above down, and from below up to get the underside of the
leaves. The oil smothers the insects.
Grubs: For lawn or garden grubs, there is a natural remedy called milky spore. The granules are spread on the soil and cause the grubs to contract a disease that kills them. This natural control affects only the grubs, leaving the beneficial organisms
unharmed. Milky spore multiplies over time and will sit inactive, waiting for grubs to infect. One treatment is said to last 40 years. The grubs are actually the larvae of Japanese beetles. So, when you kill the grubs you kill the beetle.
Mites and other insects: Mix two tablespoons of hot pepper sauce or cayenne pepper with a few drops of Ivory soap into a quart of water. Let stand overnight, then stir and pour into a spray bottle and apply as above. Shake container frequently during
Earwigs, slugs, and other soft-bodied garden pests: Sprinkle diatomaceuos earth over plants and around edges of garden beds. The diatoms particles are very small and sharp – but only harmful to the small exoskeletons of insects, slugs and snails. Insects
cannot become immune to its action, as it is a mechanical killer – not a chemical one.
Fungal diseases: Mix two tablespoons of baking soda into a quart of water. Pour into a spray container and spray affected areas. Repeat this process every few days until problem ceases.
Powdery mildew: Mix equal parts milk and water and spray on infected plants. Three treatments a week apart should control
Insects and fungal diseases: Combine one tablespoon of cooking oil, two tablespoons of baking soda and a few drops of Ivory soap into a quart of water. Pour into a spray container and apply as above.
Insects on fruit trees: Lime sulfur and dormant oil, available at nurseries and garden centers, can be sprayed on the trunk and branches of dormant fruit trees. This concoction will suffocate insect egg cases. Because the oily spray is heavy compared to the other water-based sprays, you'll need a pump sprayer. These are fairly inexpensive, and are available to rent from some nurseries. Only use this method while the tree is dormant, however, or it can kill the tree.
Commercial dormant oils may contain petroleum oil or kerosene. A less toxic method is to make your own. Mix 1 cup vegetable oil and 2 tbsp liquid soap in one gallon (4 liters) water. Mix the soap and oil first, then add the water. Shake often during use.
Caution: Sprays which kill harmful insects will also kill beneficial insects. Use these homemade remedies selectively, only spraying the infected plants. Apply them early in the morning or just before dark. Re-apply after a rain. Wear protective
clothing when spraying insecticides.
· Protect your young seedlings from animals and snails or slugs.
WHY GROW HEIRLOOM PLANTS
One reason to grow heirloom vegetables is simply that they are a taste of the past. Many varieties, which had been prized and maintained for generations, have been lost in recent decades as fewer people save seed year to year. For many gardeners, saving an heirloom cultivar is a connection to their heritage.
Many gardeners grow heirlooms that have superior flavor. Heirloom varieties that have been selected for taste and tenderness through several generations are often tastier than cultivars that have been selected for ease of shipping, uniform appearance or ability to grow well through out the country.
When gardeners save the seed of the best-tasting, best-performing plants in their gardens each year for a number of years, they gradually select their own special cultivars. Those selections will be suited to their own growing conditions and tastes. Open-pollinated seed that has been grown and harvested for generations in a region or microclimate becomes adapted to that area’s soil, climate and pests.
Many people grow and save old cultivars because they save a lot of money by avoiding the purchase of new and expensive hybrid seed each year. Hybrid seed will not produce similar plants when saved from year to year. Another vital reason to maintain heirlooms is to keep their genetic traits for future use. When old varieties of food crops are not maintained, the gene pool grows smaller and smaller. This may lead to increased disease and pest problems.
If you grow heirloom vegetables, you will almost certainly save seed. More and more companies are beginning to carry old cultivars in their seed list, but most heirloom gardeners want to ensure their seed supply against changes in fashion. Many also feel that saving their own seed gives them more connection to the entire process of growth and regeneration.
Do not try to save seed from hybrid vegetables. It will not produce plants the same as those from which it is collected. Saving seed can duplicate open-pollinated cultivars, if the crop is not allowed to cross with other strains of related vegetables.
There are several ways that home gardeners can maintain their seed stock without unwanted crossing. Some vegetables are mainly self-pollinating; their seeds will produce plants like the parent plant that produced the seeds.
Beans, peas and peanuts, lettuce, eggplant, peppers, and tomatoes are usually self-pollinating. Insects occasionally cross them, so plant them with at least 10 feet between varieties.
Beans and tomatoes are very popular as heirloom vegetables partly because they are easily maintained true to type.
Vegetables that are cross-pollinated by insects or by wind need to be isolated or raised at a considerable distance from other varieties. This distance may need to be several hundred yards or more, depending on the crop.
Onions, cucumbers, corn, pumpkins, squash, broccoli, beets, carrots, cabbage, cauliflower, melons, radishes, spinach, Swiss chard and turnips are all insect-or wind-pollinated. In a small garden, the easiest way to ensure purity is to grow not more than one variety of a species at a time. If your goal in raising an heirloom variety is to preserve it, you do not want it to cross with something else.
One way to isolate cultivars is to grow them in separate screened cages, or to cover individual flowers with bags and hand-pollinate them. Another method is called time isolation. Time plantings so that different varieties are not flowering at the same time and so cannot pollinate each other.
Choose plants to save seed from before you harvest the rest of the crop to eat. You should choose the healthiest, most productive and most flavorful plants to save for seed. Make sure that you label them clearly for seed to avoid temptation.
Allow seeds to ripen fully before they are harvested. Mature seeds are more likely to grow well than seeds harvested too soon. Strong, healthy plants produce healthier seeds than seed from weak, stressed plants.
Warm, dry conditions while seed matures increases their storage life. It is best to harvest your seeds and bring them inside for final drying as soon as they are fully mature and dry, especially if rains threaten
Most vegetable seeds remain viable for three to five years when stored properly. Place thoroughly dry seed in a tightly closed glass jar and keep the jar in a cool dry location. Put silica gel packets in with the seed to help keep it dry. You can add diatomaceous earth to seed to help prevent insect damage. Store seed in the refrigerator to further increase its life expectancy.
To test for germination, sprout seeds between moist paper towels; if germination is low, either discard the seeds or plant extra to give the desirable number of plants.
Long-lived seeds include beets; all cabbage relatives such as broccoli, cauliflower, collards, and kale; cucumber; lettuce; melons; peppers; sunflower; tomato; and turnip. If you keep them cool and dry, these seeds should maintain good viability for five years or more.
Medium-lived seeds include beans, carrot, chard, eggplant, parsley, peas, pumpkin and squash. These, properly stored, should last at least three years.
Short-lived seeds can only be depended on to last to the next growing season. This list includes corn, leek, onion and spinach seed.
HEIRLOOM VEGETABLE CULTIVARS
Beans of all kinds are very popular heirloom vegetables. There are thousand of cultivars, with huge variations in taste, size, color and markings, and climate adaptability.
Beans are usually not cross-pollinated. Separate plantings by enough distance to avoid having their vines intertwine.
Allow the seed to thoroughly mature on the vine. Pull the entire plant and place it in the shade to dry out for one to two weeks. Bring inside to finish drying if rain threatens. Shell and store in a cool, dry area in a paper bag. Bean and cowpea seeds will keep for three or more years.
Lima and Butter Beans
‘Christmas Lima’ does well in hot, humid climates. Climbing vines produce large seeds that are white with maroon streaks and have a wonderful flavor.
‘Snow on the Mountain’ is a beautiful, heavy-producing pole lima from the 1800s. It has deep maroon seeds with white markings.
‘Jackson Wonder Bush’ is a productive and drought-tolerant 1880s vintage heirloom from Georgia. Purple and black mottling. 66 days.
Pole, Snap And Dry Beans
‘Cherokee Trail of Tears Pole’ These heirloom pole beans were carried by Cherokee Indians on the "Trail of Tears." Purple-striped pods with shiny black seeds.
‘Greasy Cutshort Pole’ has leaves that are shiny, giving a greasy appearance. Good eaten as snap beans.
‘Jacob’s Cattle’ is a small, pretty bean, pure-white with deep maroon splashes. Excellent quality for baking and soups.
‘Rattlesnake Pole’ has purple-streaked 7-inch green pods that curl like snake. The buff-colored beans with black stripes are good as shell beans or snaps. Vines grow 10 feet tall.
‘Tongues of Fire’ is an early snap bean with beige and brown markings. Excellent flavor.
All corn is wind-pollinated and will readily cross with other varieties. Varieties should be widely separated, from 600 feet to over half a mile to ensure purity. You can also save seed by bagging the ears that you want to save for seed and hand-pollinating them, or by growing cultivars that will be separated by blooming time. You should always grow at least 200 corn plants in a large block when saving seed. Save seed from 50 ears of different plants to reduce inbreeding depression. Let the seed dry thoroughly on the plant and then dry further once husked. Seed lasts only one year.
‘Golden Bantam’ was first introduced in 1902. This is the corn all others were compared to.
‘Country Gentleman’ is a popular old-fashioned shoe peg variety with irregularly spaced white kernels.
‘Stowell’s Evergreen’ was the standard, late-season white sweet corn before ‘Silver Queen.’ Ears are 8 to 9 inches long.
‘Bloody Butcher’ is a flint corn used for flour-making or decoration. The ears are bright red.
‘Strawberry Popcorn’ an old variety, grows 2-to 3- inch ears that are excellent for decorations in the fall, then popping in the winter.
There are many different forms of cucumbers that are rarely seen in stores. Cucumbers are cross-pollinated by insects. So if you want to save cucumber seed, plant only one variety. Let the fruits hang on the vine until ripe (skin becomes yellowish and hard). Then handle like the process for tomatoes given below.
‘Lemon’ produces many lemon-colored and lemon-shaped fruit on fast-growing vines.
‘White Wonder’ is an old variety that matures to an ivory white color. The 7-inch fruit are easy see at harvest.
Cut off seed stalks when fluffy in appearance, just before all the seeds are completely dried. Seeds will fall off the stalk and be lost if allowed to mature on the plant.
‘Deer Tongue’ is a pre-1900 heirloom that is named for its pointed leaves and thick mid-rib. It is heat-tolerant and slow-bolting.
‘Tennis-ball’ was a very popular lettuce in the vegetable garden at Monticello. Tennis-ball lettuce has been grown since the late 18th century, and it is the parent of Boston lettuce types.
Treat melons in the same way as cucumbers.
‘Jenny Lind’ grows to 1 to 2 pounds with sweet, lime-green flesh. An heirloom from New Jersey, it was named in 1846.
‘Hearts of Gold’ is a very popular old-timer. The 3-pound melons have thick, fine-grained flesh with spicy flavor. Flesh is salmon-orange in color.
Potatoes are popular heirloom vegetables. There are many unusual colors, shapes and flavors that are seldom found at the grocery store. Heirloom potatoes are saved from year to year as tubers, and so are very easy to maintain true to name.
‘Russian Banana’ is a fingerling potato that is yellow-fleshed with a pleasantly waxy texture. It varies from fingersize up to the size of an actual banana.
‘Yellow Finns’ are medium-size, with yellow skin and yellow flesh.
‘Ruby Crescent Fingerling’ has small tubers between 2 and 6 inches long. Ruby-red skin covers deep yellow flesh.
Okra pods should be left on the stalk until brown and well-matured. Remove the pods and place them in the shade until thoroughly dried. It is best to store okra seed in the pod until ready for planting.
‘Longhorn’ has long pods that are tender up to 6 or 8 inches long. It dates from the 1880s.
Peppers, Sweet and Chili
Peppers are usually self-pollinating. Insect cross-pollination does occur sometimes, and if it does, hot bell peppers can result, since the gene for hotness is dominant. If grown closer than 500 feet apart, plants must be caged or bagged to prevent spicy surprises in future years.
Peppers should be allowed to ripen until they become red. Cut the pepper pod in half and scrape the seed onto a piece of paper. Spread out the seed and dry thoroughly before placing in a storage container.
Wash your hands thoroughly with soapy water after harvesting the pepper seeds, since the residues will burn eyes and lips for hours after contact.
Southern Peas or Cowpeas
Southern peas are handled in the same way as beans.
‘Calico Crowder’ is a medium-sized, heirloom, climbing crowder pea, white with maroon splotches, good fresh or dried. 70 days.
‘Kreutzer’ is an excellent cowpea which produces quantities of attractive beige-and-brown cowpeas with darker brown specks.
‘Pink-Eye Purple-Hull’ has cream-colored seeds with maroon eyes in pods which turn purple at maturity. Vigorous, heat-loving and drought-tolerant plants with little vining.
‘Washday’ is so named because they cooked up fast on busy washdays. This tan-yellow variety is a good yielder that makes a tasty soup. It is a half-runner type from the 1800s.
Squash and Pumpkins
Winter and summer squash and pumpkins are all related. Crossing readily occurs between varieties of the same species. No crossing occurs between different species. Grow only one variety of the same species, and separate by ½ mile or hand pollinate to maintain purity.
The commonly grown species are: banana, buttercup, cushaw and hubbard squash (Cucurbita maxima); butternut squash (Cucurbita moschata); acorn, crookneck, and scallop squash, zucchinis and most pumpkins (Cucurbita pepo); and Mexican gourd (Cucurbita ficifolia).
When the outer covering of the squash is so hard that it cannot be dented with your fingernail, the seeds are generally mature. Split the squash fruit open, scoop out the seed and wash until all pulp is removed. Spread out on newspaper to dry.
‘Cushaw Green-Striped Squash’ (C. mixta) has good-sized white fruits with green stripes and long, curved necks. It is good for pies and baking. Drought-tolerant and a good keeper.
Pumpkins and Related Squash (Cucurbita pepo)
‘Rouge Vif d’Etampes’ is also known as the Cinderella pumpkin. This French heirloom pumpkin is productive and beautiful. The fruits are flat, burnt orange to red, and deeply ridged, ranging from 1 to 2 feet across.
‘Connecticut Field’ is an old standard in field pumpkins. Large 20 to 35 pounds.
‘Small Sugar’ is a sweet, tasty pumpkin to 9 inches across, on short, space-saving vines.
The Amish Paste is holding up better than our hybrid Romas under this type of stress, though the
yield is definitely less.
Tomatoes are self-pollinators and are usually not cross-pollinated. Only the potato leaf varieties must be separated.
Pick fruit from desirable plants when ripe. Cut fruit and squeeze out pulp into a container. Add a little water and let ferment two to four days at room temperature, stirring occasionally. When seeds settle out, pour off pulp and spread seeds in a thin layer to dry thoroughly. Store in an envelope or glass jar in a cool, dry place. Properly stored seeds will remain viable for four to 10 years.
‘Brandywine’ is the most famous heirloom tomato. This Amish heirloom originated in Chester County, PA, in 1885. The flavor and texture are superb. Fruit quality stays high late in the season. The plant often appears disease resistant. This "potato-leaf" variety makes a half to a pound pinkish-red fruits.
‘Cherokee Purple’ is one of the most widely adapted of the "purple" or "black" tomatoes. The flesh inside is brick red and soft, and it has good flavor. Pinkish-brownish-purplish delicious fruits on indeterminate vines.
‘Georgia Streak’ is a yellow and red beefsteak indeterminate heirloom from Georgia. Makes great-looking slices for summer salads.
‘Yellow Pear’ has prolific vines that produce loads of 1- to 2- inch pear-shaped fruits with good flavor.
‘Arkansas Traveler’ produces medium-sized, dark-pink tomatoes on heat-tolerant vines.
‘Mortgage Lifter’ produces pink to red, medium-sized to large fruit. Also called Radiator Charlie’s Mortgage Lifter.
‘Moon & Stars’ is another heirloom from the Amish. These 15- to 30- pounds melons have sweet red-pink flesh. The dark green rind is covered with bright yellow spots. The leaves of the plants are also spotted.
Clemson University Cooperating with U.S. Department of Agriculture, South Carolina Counties, Extension
Service, Clemson, South Carolina,