Vegetables need a certain range of temperatures in order to grow well. Peas and spinach thrive in the cool days of early spring. Tomatoes and peppers, on the other hand, resent cool temperatures and simply won’t grow until summer days begin to heat up.
Cool-Season Vegetables
The cool season is that time of year when night temperatures stay above about 25°F (-4°C) and below 60°F (16°C). The length of time cool weather lingers differs every year, but a typical cool season ranges from less than 60 days in the far North and Deep South to more than 100 days elsewhere.
Many cool-season crops are planted in staggered sowings to ensure a constant supply of vegetables. A safe general rule is to plant seeds every 10 to 14 days. This rule doesn’t always work, however, because conditions in the garden change over the course of the season. As temperatures warm or cool and moisture concentrations change, the growth rates of the plants increase or decrease.
A typical cool season ranges from less than 60 days in the far North and Deep South to more than 100 days elsewhere.
To time your staggered crops more exactly, sow the second plantings of root crops and greens, such as radishes and spinach, when the first seedlings show their first set of true leaves. For crops such as peas, make successive plantings when the seedlings are as tall as your index finger.
Cool-Season Crops
arugula, roquette
beets
broad beans
broccoli
broccoli raab
Brussels sprouts
cabbage
cauliflower
Chinese cabbage
collards
corn salad
endive
Florence fennel
kale
kohlrabi
lettuce
parsley
parsnips
peas
radicchio
radishes
red mustard
spinach
turnips
Warm-Season Vegetables
Planting the warm-season vegetable garden marks the end of the long transition between winter and summer and from indoor to outdoor gardening. The soil is warm enough to foster the growth of tender seeds, and the corn, tomato, and pepper plants explode with life.
Some of the plants of the warm-season garden are hold-overs from spring. Carrots, potatoes, and Swiss chard can all stand cool weather, but unlike other cool-season plants, they can also tolerate or even thrive in the warm days of summer. Other warm-season crops, such as tomatoes, corn, and snap beans, evolved in the semitropical regions of the world, where cool nights alternate with warm days for most of the year. This is still the best environment for their cultivated relatives; the best crops are grown where the summer nights are at least 15 degrees cooler than the days.
Keeping so many plants with such different likes and dislikes happy in one garden is a bit of a challenge, but it doesn’t have to be a daunting one. Even though these plants are a varied group, they still have much in common. All of them thrive in evenly moist soil rich in organic matter and bathed in sunshine. There are some subtleties to master, but they make the resulting accomplishments that much sweeter.
Plant seeds of cucumbers and beans when apple blossoms fall.
Warm-Season Crops
artichokes
asparagus
bush beans
carrots
celery
corn (sweet and pop)
cucumbers
eggplants
garlic
leeks
muskmelons
okra
onions (bulb)
peanuts
peppers (sweet)
pole beans
potatoes
pumpkins
rhubarb
squash (summer and winter)
sweet potatoes
Swiss chard
tomatoes
watermelons
Planting Phenology
Phenology is the science of using indicator plants to determine when certain weather conditions will prevail and certain insect pests will be active. Here’s how you might use phenology to guide your plantings:• Plant Swiss chard, spinach, beets, and onions when the daffodils bloom.
Plant peas when the maple trees flower.
Plant potatoes when the leaves of white oaks are the size of a cat’s ear.
Sow bush beans, pole beans, and cucumbers when apple trees drop their petals.
Transplant tomatoes, melons, and eggplants when black locust trees and peony bushes flower.
Transplant just before it rains, so the new transplants get well watered. Watch for swallows swooping close to the ground over fields. The insects they eat fly closer to the ground before it rains.
Extending the Season
Season extenders help you get more from the growing season in two ways: by protecting tender crops from the ravages of a late-spring frost and by helping the soil heat up quickly for warm-season crops.
Plant Protectors: Extending Your Growing Season
In some respects, the term “extenders” is a misnomer. More than adding a few weeks to the start or end of a season, extenders actually modify the climate. They protect from not just frost but also wind, pests, rain, and snow. Low-cost, old-fashioned season extenders that remain popular include cold frames, plastic cones, hot caps, plastic milk jugs with bottoms cut away, hay bales, newspaper, blankets, plastic-wrapped wire frames, and even grocery bags with their edges turned down and weighted with soil. All work well in certain situations. We’ll examine a few in some detail.
Row Covers
Row covers are extenders that protect your plants. There are two main kinds: floating and plastic.
Floating row covers are soft, white “garden blankets” made of lightweight, permeable material. They require no supports and are available in numerous weights, sizes, and thicknesses. The lighter they are, the more light transmission they allow, but the lighter ones also offer less frost protection. The thicker they are, the more frost protection they provide. But the thicker covers also generate more heat — something to watch for when the sun intensifies.
Use floating row covers immediately after transplanting tomatoes, eggplants, broccoli, melons, cucumbers, peppers, strawberries, and other heat-loving plants. Remove them when blossoms are ready for pollination or temperatures exceed 85°F (29°C). In the fall, keep covers on longer to maintain soil heat on cool evenings.
Floating fabric row covers offer protection from frost and from pests.
Plastic row covers are often perforated or slit to let rain or moisture through. They protect plants from pests, but they do not keep out all insects. The covers are laid in the form of a tunnel supported by wire hoops. Most offer only a few degrees of frost protection, significantly less than the thicker fabric row covers. They also tend to generate more heat than floating row covers, making them well suited for heat-loving plants such as cucumbers and melons.
Install plastic row covers as soon as the soil can be worked in the spring. They can increase vegetable germination and yields by as much as three weeks and 50 percent, especially in regions that experience a long, cold spring.
Plastic row covers supported by hoops generate more heat than floating row covers do. They’re best used for heat-loving crops like melons and eggplants.
Mulches, Cool and Warm
Cool mulches control weeds by blocking visible light from reaching the soil. Many differ from warming mulches in that they reflect most of the sun’s energy instead of absorbing it. Cooling mulches include straw, pine needles, and black-and-white newspaper. As they inhibit weeds, they allow water to penetrate readily. The mulch then acts as a water conservator, allowing moisture to percolate down through the soil but inhibiting evaporation. Temperatures beneath a cooling mulch can be several degrees lower than the ambient air temperature.
Starting a Hot Bed
The old-fashioned hot bed is a wonderful invention that can keep fresh lettuce on
the table just about all winter long. To build a hot bed, simply remove all the soil to a depth of 2 feet inside a cold frame. Line the earthen sides with 1- to 2-inch-thick panels of Styrofoam insulation. Add a wooden frame around the insulation to brace it, if desired. Add an 18-inch layer of fresh horse manure and firm well. Spread 6 inches of sand on top of the manure. Use a soil thermometer to track the temperature of the sand. As the manure composts, it will heat the sand to over 100°F (38°C). Place flats and pots of plants in the hot bed when the sand temperature drops below 90°F (32°C). The manure will heat the bed for many weeks. When the manure is composted, the hot bed can be used as a cold frame.
Black polyethylene mulch helps the soil warm up in spring. Seedlings can be planted directly into the plastic sheet.
There are three types of warm mulches. Black polyethylene mulch is made of 1.25-mil black plastic sheeting. It has been used for decades, but it has some disadvantages. It is not biodegradable and is often difficult to remove from the garden. Black landscape fabric works similarly. It does not warm the soil as efficiently as black poly, but the difference is slight. Unlike black poly, landscape fabric allows water to seep into the soil. IRT-100 is a dark-colored plastic that allows a good deal of energy from the sun to warm the soil directly. It then helps retain the accumulated warmth. It is the most effective soil-warming mulch to date, but it is not biodegradable.
Hot Caps
Hot caps are simple devices to protect individual small plants from frost. One option is the plastic milk container. Simply cut the bottom from a 1-gallon container and set it over the plant. Leave off the cap for ventilation. Seedlings can be protected by setting paper cups over individual plants.
The best device for frost protection is the Wall-O-Water hot cap, which consists of several plastic cylinders joined into the shape of a tepee. When you place it around the plant, fill the cylinders with water. In tests among paper cups, milk jugs, row covers, and Wall-O-Water tepees, the tepees were most effective in providing frost protection.
Homemade hot cap
Wall-O-Water hot cap
The cold frame is a boon to gardeners who wish to grow cool-season crops such as lettuce into the winter.
Hot caps give plants a head start on growth. However, if plants are not weaned from them by blossom time, yields will be smaller than those gathered from plants grown without the caps.
Cold Frames
The cold frame is a small, easily built structure used to lengthen the growing season. Traditional cold frames are most often made of wood such as redwood, white cedar, or cypress. The head-board is about 18 inches high and the footboard is about 12 inches tall. Sloping boards connect the two and serve as support structures for the window sash used as glazing. The entire structure is then set so the foot-board faces south.
The cold frame becomes a small greenhouse, letting solar energy pass through to warm the soil, then trapping the heat that radiates back. This contraption is a boon to northern gardeners who wish to grow cool-season crops such as lettuce into the winter. For maximum heat retention, line the floor with black plastic. A thermometer in the frame helps you gauge when it’s warm enough in spring to plant or hot enough to ventilate.
Cold Frame Styles
Small wood-sided cold frame
Cold frame surrounded by foam insulation
Cold frame with stone sides
You can also purchase precut cold frames made with tubular polycarbonate sheets and aluminum joiners. This kind of glazing is almost as clear as glass.
Planting Dates in Relation to Frost
Hardy
Plant as soon as ground can be prepared:
asparagus
beets
broccoli
cabbage
carrots
chard
kale
lettuce
onions
parsnip
peas
radishes
spinach
turnips
Semi-Hardy
Plant one to two weeks before average date of last frost:
cauliflower
potatoes
Tender
Plant on or just after average date of last frost:
New
Zealand
spinach
snap beans
sweet corn
tomatoes
Very Tender
Plant two weeks after average date of last frost:
cucumbers
eggplants
lima beans
muskmelons
peppers
pumpkins
squash
watermelon
Growing from Seed
If you’re trying to get the most vegetables for the least amount of money, starting plants from seed is the way to go. It takes more advance preparation but is well worth the extra effort.
Starting Your Own Plants from Seeds
You’ll need seeds, of course, but you’ll also need a few more supplies to be successful at starting plants from seeds.
Containers
Basically, anything that can hold a germinating medium and is the right size will do. Seed-sowing flats should be 3 to 3½ inches deep and can be any size, depending on how many seeds you intend to germinate. Generally the ones you buy are made of plastic or fiber.
Peat pots are good for seeds that resent transplanting and for larger seeds. These pots are usually 2½ to 3 inches across and are combined germinating-growing-transplanting units.
Peat pellets are made of compressed peat. When placed in water, they expand into units similar in function to peat pots. They are best for larger, reliably germinating seeds and seeds that resent transplanting.
Plugs are cone- or cylinder-shaped transplants. You can buy plug trays, which have up to 200 plug holes. One seed is sown into each plug hole.
You can also use things from around the kitchen, such as coffee cans, paper cups, aluminum baking trays, milk or juice containers, and plastic food-storage containers. Before using them, wash them in soap and water and rinse them in a bleach solution (1 ounce bleach per 2 gallons water). This prevents diseases that might kill your seedlings.
Containers must have excellent drainage. If you make your own, be sure to punch out some drainage holes in the bottom.
Growing Mediums
There is no one perfect germinating medium, but here is a look at some of the available choices.
Baled or bagged peat moss comes from decomposed aquatic plants. Its composition varies greatly. It is rarely used by itself for propagating or growing, because water may not penetrate it easily or evenly. However, it is widely used in sowing and growing mixtures.
Whether seed-starting containers are store-bought or recycled, they must be clean and have drainage holes in the bottom.
Sphagnum moss is relatively sterile, lightweight, and able to absorb 10 to 20 times its weight in water. It is generally milled (shredded) for use as a seed-sowing medium.
Vermiculite is expanded mica. It holds tremendous amounts of water for long periods of time and contains a high percentage of magnesium and potassium, two elements necessary for good root growth. Although it is not usually used alone for seed germination, it is an excellent addition to a mix.
Perlite is a volcanic ash that stays cool and is therefore good in mixes used for germinating seeds that prefer lower temperatures. However, it will float to the surface when the seedbed is watered. Use the finest grade for seed germinating.
Soil from the garden should not be used to germinate seeds, unless it is first sterilized to kill weed seeds and fungi. To sterilize it, bake it in a shallow pan at 180°F (82°C) for 30 minutes. Be prepared for an unpleasant odor.
Mixtures of peat or sphagnum moss with vermiculite and/or perlite are the best mediums for germinating seeds. You can buy these ready-made or make them yourself, using 1/3 to ½ sphagnum or peat moss and vermiculite, perlite, or a combination of the two for the rest.
Double-Dig Your Garden
At about the same time that you are starting seeds, you might also start thinking about one of the best treatments for your garden: double digging.
1. Dig a trench about a foot wide and as deep as your shovel. Place soil on a tarp or in a cart.
2. Drive the tines of a garden fork or a broadfork as deep as you can into the bottom of the trench. Rock the handle back and forth to loosen the subsoil. Spread a little compost over the loosened soil.
3. Dig another trench alongside the first, turning the removed soil into the first trench. Continue to the far end of the bed, and fill the last trench with the soil from the first trench.
Five Easy Steps to Sowing Seeds Indoors
1. Fill a flat to within ¼ inch of the top with potting mixture and level the surface with a piece of wood.
2. If you are going to plant the seeds in rows, use the edge of the wood to make ¼-inch troughs in the soil. Other -wise, spread the seeds over the soil, evenly and not too thickly, then press them in with the flat side of the wood.
3. Cover them, remembering that they should be buried to a depth of about four times their own diameter. Try to make sure that you spread an equal amount of soil over the whole area.
4. Use a flat piece of wood to firm the soil a second time. Newly planted seeds should be watered liberally but gently — preferably with a fine spray.
5. Last, the flats or pots should be put in plastic bags or covered with plastic to seal in moisture. You should not have to do more watering until the seedlings emerge (at which point, the plastic should be removed).
Suspend standard fluorescent lights 8 to 12 inches above seedling trays.
Helping Your Seeds Germinate and Grow
Provide your seeds with the following environmental conditions:
Light. Place them near a sunny window with a southern exposure or under cool-white fluorescent bulbs. If they are by a windowsill, turn newly sprouted seedlings regularly so they will grow straight and evenly.
Warmth. Most seeds germinate and grow best in a spot where the temperature remains 70 to 75°F (21 to 24°C). Most seedlings prefer normal room temperatures of 60 to 70°F (16 to 21°C).
The Backyard Homestead Page 3