Potatoes, Peppers, Eggplant (Solanaceae) - Growing Facts
Most vegetable plants should not be over 6 weeks old when they are set in the ground. That means tomatoes grown in Zone 4-5 are not seeded until late April, since they will not be planted until after May 25th (last frost date). Seeds should be about 1/4" apart to avoid damping-off fungus. Check every day and when seedling emerges, transfer immediately to a grow light, or they will grow leggy and result in a weakened plant. Thin out scrawny seedlings, leaving stronger ones about 2" apart, so enough light and air circulation will reach the tender stems.
Johnny's Seeds warns on the seed package that it takes 10-21 days for peppers to germinate. We use heating pads, sold by many seed catalogues, to speed up germination time. The hotter peppers (piquin, chiltepin [bird pepper] and habanero seem to take about a week longer to germinate than jalapeno, cayenne, and bells.
Some potato varieties are more drought tolerant than others. Research by USDA scientists showed that under dry conditions, Nooksack potatoes produced up to 60 percent U.S. Grade No. 1 potatoes, while Russet Burbank potatoes only yielded 40 percent high-grade tubers. When spring is prolonged and soil is too wet to work, Virginia Tech Extension suggests laying seeding the eye up on top of the ground, 12" apart, and laying 6" of oak leaves on top, watering well to prevent leaves from blowing off.
Source: Virginia Tech Extension Serv., Blacksburg VA, Adapted by
Diane Relf, Extension Specialist, Environmental Horticulture, and Alan McDaniel,
Extension Specialist, Horticulture, Virginia Tech Publication Number 426-413, posted June
SOIL: Well-drained with moderate organic matter.
pH: 4.8 to 6.5
TEMPERATURE: Cool (55 TO 65°F).
MOISTURE: Uniform moisture, especially while tubers are developing.
PLANTING: Plant 1 1 /2 - to 2-ounce seed pieces with at least one good eye in
early spring; will resist light frost.
SPACING: 10 to 12 inches by 24 to 36 inches.
FERTILIZER NEEDS: Medium-heavy feeder. Add high phosphorus fertilizer before
planting, using 2 1/2 lbs. 5-10-10 per 50-foot row. Sidedress 1 or 2 times after
tubers begin forming using 1 lb. 10-10-10 per 50-foot row.
Both white-skinned and red-skinned potatoes can be grown as an early crop for new potatoes and as a late crop for storage. Choose an early maturing variety and a medium- to late-maturing variety. Plant potatoes early from March 15 to April 20, depending on your location. Hard frosts and freezes may set back growth. Potatoes prefer cool springs and moisture throughout the growing season. Crops can be successfully planted as late as June for fall harvest and storage, but yield may be reduced.
Avoid a garden site in a turned-under lawn as grub worms may damage developing tubers
unless soil insecticides are used.
A soil pH of 6.0 to 6.5 is most desirable; however, scab disease will be less when the pH is between 5.0 to 5.2. Work this into the furrow and mix with the soil before planting.
Purchase certified seed stock that has been inspected for diseases that lower yields. Saving your own seed potatoes is generally not worthwhile because viruses and diseases often show up the next year. Seed potatoes should be firm and unsprouted. Wilted and sprouted potatoes usually have lost vigor from being too warm in storage.
Seed pieces for planting should be cut to about 1 1 /2 to 2 ounces or into 1 1 /2 -inch cubes. Potatoes about 6 ounces in size will cut into four pieces
nicely. Each seed piece should have at least one good bud or eye. Allow to dry or cure before planting. Plant potatoes in furrows cut-side down, 3 to 5 inches deep. Later crops should be planted 5 to 6 inches deep.
Chitting, a controlled sprouting of the seed potato, is an old English technique for forcing potatoes. Early varieties respond best. Place potatoes in a cool room (55°F) with indirect light. Short, sturdy green sprouts about 1 /2 inch long will develop in about one month, providing sprouted seed potatoes for planting. Use care not to break sprouts.
Pull a ridge of soil over each row when planting. Drag a board or hoe across the ridges just before the sprouts break through to eliminate weeds. Later
cultivation should be shallow and far enough from the rows to make certain that no roots are damaged.
When the tops have grown too large to allow cultivation, a finishing cultivation, sometimes called laying-by or hilling-up, is given. Laying-by
throws soil over the potatoes to prevent exposure of the potatoes to sun which can cause greening or scalding. Green portions on potatoes taste bitter and contain an alkaloid. Cut off and discard green areas before using. An alternative of planting in areas with heavy clay soil is to grow plants in
straw or leaf beds above ground. This requires 2-3 feet of organic matter and more frequent watering than in ground production but produces clean, easily dug tubers.
DISEASES: Early blight; scab; late blight; tuber rots; virus complex; and fusarium, verticillium, and bacterial wilts.
INSECTS: Colorado potato beetles, flea beetles, leafhoppers.
CULTURAL: Green skin from sun exposure; hollow heart from alternating wet and
dry conditions; Black Walnut wilt from being too close to a Black Walnut tree.
Water stress in sweet potatoes can result in cracked roots. A potassium deficiency causes long, slender roots. Too much nitrogen reduces yield and
quality. If your potatoes are visible along the soil surface, the portion exposed to light will turn green. Green-skinned potatoes will taste bitter and can cause sickness, so protect tubers from light by covering them with soil or mulch. Withhold water on storage potatoes when they begin to die down. Water and fertilizer late in the season may disturb dormancy necessary for good storage. They can cause regrowth or cause potatoes to crack prior to harvest
Harvest and Storage
DAYS TO MATURITY: 100 to 120 days.
HARVEST: Dig early potatoes when tubers are large enough to eat. Harvest potatoes for storage two weeks after the vines die down or just after the first light frost nips the vines, before heavy freezing. Avoid skinning tubers when digging and avoid long exposure to light.
APPROXIMATE YIELDS: 6 to 15 pounds per 10-foot row.
AMOUNT TO RAISE: 75 to 100 pounds per person (about 15 pounds of seed potatoes).
STORAGE: Medium-cool (40 to 50°F), moist (90% relative humidity) conditions for six to
eight months. Sprouting is a problem at higher temperatures.
PRESERVATION: Medium-cool, moist conditions.
SOIL: Well-drained, loose soil with moderate organic matter.
pH: 5.5 to 6.5
TEMPERATURE: Warm (70 to 75°F).
PLANTING: Set out transplants after soil has thoroughly warmed in the spring. Start seed indoors six to eight weeks prior to this date.
SPACING: 18 to 24 inches by 30 to 36 inches.
FERTILIZER NEEDS: Light to medium feeder. Use starter solution for transplants. Sidedress cautiously after first fruit sets with 3 tablespoons 33-0-0 per 10-foot row; too much fertilizer may cause excessive vegetative growth.
Most peppers are classified according to their degree of hot or mild flavor. The mild peppers include Bell, Banana, Pimiento, and Sweet Cherry, while the hot peppers include the Cayenne, Celestial, Large Cherry, and Tabasco. Bell peppers, commonly measuring 3 inches wide by 4 inches long, usually have 3 to 4 lobes and a blocky appearance. Green bell peppers can be left to turn red or yellow when fully ripe. Some varieties now produce orange, purple, yellow or even chocolate colored fruit. About 200 varieties are available.
Banana peppers are long and tapering and harvested when yellow, orange, or red. Another sweet pepper, Pimiento, has conical, 2 to 3 inches wide by 4 inches long, thick-walled fruit. Most Pimientos are used when red and fully ripe. Cherry peppers vary in
size and flavor. Usually they are harvested when orange to deep red. Slim, pointed,
slightly twisted fruits characterize the hot Cayenne pepper
group. These can be harvested either when green or red and include varieties such as Anaheim, Cayenne, Serrano, and Jalapeno. Large cherry peppers are very hot - more mild than Serrano, but hotter than Jalapeno. Celestial peppers are cone shaped, 3 /4 to 2 inches long, and very hot. They vary in color from yellow to red to purple, making them an attractive plant to grow. Slender, 1- to 3-inch, pointed Tabasco peppers taste extremely hot and include such varieties as Chili Piquin and Small Red Chili.
Peppers generally have a long growing season and suffer slow growth during cool periods. Therefore, after the soil has thoroughly warmed in the spring, set out 6- to 8-week-old transplants to get a head start toward harvest. Practice good cultivation and provide adequate moisture. Mulching can help to conserve water and reduce weeds. Hot peppers are usually allowed to fully ripen and change colors (except for Jalapenos) and have smaller, longer, thinner, and more tapering fruits than sweet peppers. Yields are smaller for hot peppers.
DISEASES: Tobacco mosaic virus, bacterial spot, anthracnose.
INSECTS: Aphids, flea beetles, cutworms, European corn borer.
CULTURAL: Blossom-end rot from moisture irregularities or calcium deficiency;
blossom drop from night temperatures rising above 75°F or excessive fruit set on
Harvest and Storage
TO MATURITY: 100 to 120 days from seed; 70 to 85 days from transplants. HARVEST:
Harvest sweet peppers when they reach full size. For maximum yield harvest while
still green. When allowed to mature on the plant, most varieties turn red,
sweeten, and increase in vitamins A and C content. Cut instead of pulling to
avoid breaking branches. Most hot peppers are allowed to ripen and change color
on the plant. Entire plants may be pulled and hung just before full frosts.
APPROXIMATE YIELDS: 2 to 8 pounds per 10-foot row.
AMOUNT TO RAISE: 3 to 10 pounds per person.
STORAGE: Medium-cool (45 to 50°F), moist (95% relative humidity) conditions for
two to three weeks.
PRESERVATION: Freeze; use in pickles and relishes or dried as spices.
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SOIL: Well-drained, high organic matter.
pH: 6.0 to 7.0
TEMPERATURE: Warm (70 to 85°F).
PLANTING: Transplant after danger of frost, when soil is thoroughly warm.
SPACING: 18 to 24 inches by 30 to 36 inches.
HARDINESS: Very tender annual.
FERTILIZER NEEDS: Heavy feeder; use 3 tablespoons of ammonium nitrate 33-0-0 per 10-foot row. Before planting broadcast 3 lbs. 10-10-10 per 100 square feet. Use a starter solution on transplants. Sidedress 1 lb. 10-10-10 per 100 square feet 3 to 4 weeks after planting and repeat in one month if needed. When fruits are swelling, apply a high potash tomato fertilizer.
The standard eggplant produces egg-shaped, glossy, purple-black fruit, 6 to 9 inches long. The long, slender, Japanese eggplant has a thinner skin and more delicate flavor. Both perform well in containers. Warm to hot weather throughout the season is necessary for good production.
Seeds germinate quickly at 70 to 90°F; and plants should be grown for eight to ten weeks before setting them out. Cold temperatures will stop plant and root growth, reducing plant vigor and yields. Use hot caps, cloches, or Wall-O-Waterto protect plants from cold conditions.
Though eggplants do well in hot weather; they must have well-drained soil and do not thrive in very humid areas. When plants are about 6 inches high, nip back the growing tip to encourage branching. Pick fruits when immature, about 2 /3 maximum size. Mature fruit should not be left on the plant as this will reduce overall productivity. Because of the eggplant's susceptibility to verticillium wilt, rotate plantings with other crops on the same garden soil.
DISEASES: Verticillium wilt.
INSECTS: Flea beetles, aphids, lace bugs, Colorado potato beetle, red spider mites, whitefly.
Harvest and Storage
DAYS TO MATURITY: 100 to 150 days from seed; 70 to 85 days from transplants.
HARVEST: Fruit should be large, shiny, and uniformly deep purple in color. When the side of the fruit is pressed slightly with the thumbnail and an indentation remains, the fruit is ripe. Long, slender, Japanese eggplant may be ready to harvest from finger or hotdog size. When fruit is dull in color and has brown seeds, it is too ripe and should be discarded. Cut fruit from plant to avoid damage.
APPROXIMATE YIELDS: 20 pounds per 10-foot row.
AMOUNT TO RAISE: 12 pounds per person.
STORAGE: Cool (45 to 50°F), moist (90% relative humidity) conditions for one
PRESERVATION: Freeze, pickle.
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Virginia Cooperative Extension