How to Manage Pests

Cultural Tips for Growing Potato

In This Guide

Site selection

Plant your garden in a convenient location, where you can check it frequently. Choose an area near an abundant supply of water so you can water as needed easily. Vegetables do best if they receive full sunlight (at least 4 to 6 hours a day). Plant them in a well-exposed area in the garden, where they are not shaded by trees, fences, or walls. Try to plant away from areas that will be watered by lawn sprinklers.

Whenever possible, select a location that is not heavily infested with weeds, especially weeds such as field bindweed, nutsedge, and Bermudagrass that can be hard to control with hand weeding. Also avoid areas that have had previous disease problems.

Try to plant on level ground. Level ground is easier to work on than sloping ground. Vegetables will do well on a wide range of soils; they do best in well-drained soils. If your soil forms a clump when squeezed, then it is too wet; if the soil crumbles easily, it is a good soil to use. Damp soil surfaces encourage snails, slugs, sowbugs, and root diseases; fruit decay and leaf spot diseases may also increase. Soil amendments can make clay and sandy soils easier to work with, and correct soil preparation can improve poor soil.

Adding organic matter (compost, peat moss, manure, sawdust, ground bark) makes clay and sandy soils easier to work with. The soil should be kept at a pH level of 6.0 to 6.5. Lime or gypsum can be added to soils low in calcium.

Soil recommendation

Sandy loam soil that is well drained and able to retain moisture uniformly.

Soil improvement

Any type of soil can be improved with soil amendments. Heavy clay or sandy soils can be improved by adding organic material such as compost, manure, or leaf mold. Texture is an important consideration when choosing an amendment. An amendment that is granular and fine grained is important for container mixes. For gardens, a more coarse-grained amendment can improve drainage and aeration. Work amendments into soil by rototilling, raking, or double-digging.

Soil preparation

The preparation of your soil is just as important as adding fertilizer and soil amendments. Before working the soil, make sure it is moist but not thoroughly wet.

1. Use a shovel, rototiller, metal bow rake, or all of them together to loosen the top 1 to 2 inches of soil. Rake the area to remove weeds and old crop debris. Be sure to dig out roots.
2. Irrigate the plot deeply to encourage the germination of weed seeds.
3. In a week or two, after a substantial number of weeds have germinated, work the area again to kill the weed seedlings. Be sure to break up the clods in the soil, as seeds planted in cloddy soil will germinate poorly and won't live long because the soil dries too quickly.
4. Form soil into beds if desired, and plant while soil is still wet.

Time to plant

Potatoes are warm-weather plants. They like sunshine and produce best when planted in a well-exposed area in the garden. The shoots of potato plants are sensitive to frost so they may need some protection in colder areas of the central valley. They can be planted 1 to 4 weeks before the last frost date, depending upon the soil temperature.

Planting Potatoes

Potatoes can be planted from seed. However, the resulting tubers take longer to produce and have more variation at harvest than do potatoes that are planted from seed potatoes. If planting from seed, plant on raised beds made by adding large amounts of sifted compost or other soil amendments so that a bed is established above the previous level of soil. Seeds can also be started indoors in flats, peat pots, or other small containers 8 weeks before the last frost date. After the danger of frost has passed, transplant into the garden. Seed potatoes can also be planted in mulch piles or in cages. Plant seed pieces the same as above. Loosely shake mulch over the bed until it is 6 to 10 inches deep. As the plants grow, continue to add more loose straw. Keep tubers covered at all times. To plant in cages or bins or cribs, again plant the same way, covering the plants with 4 inches of soil. After the plant emerges, continue to add well-aged compost, mulch, or soil. Because the cage is above ground, potatoes dry out quickly, so this method will require more frequent irrigation.

When transplanting potatoes, place the seed pieces or whole small seed potatoes into 3-inch deep furrows, spaced 6 to 12 inches apart. The closer the spacing the smaller the harvested potatoes will be. Fill the furrows to ground level with soil. Leave them until the shoots emerge from the soil. Once the shoots are about 8 inches long, gently hill them over with more soil. Leave about 4 inches of the top of the plant exposed. Repeat this operation once again in about 2 to 3 weeks and then once more in another 2 weeks. Avoid damaging the plant.

Certified seed pieces

Use seed pieces that are certified to be free of pests and diseases, and not of a named cultivar. Do not use grocery store potatoes. Use tubers that are cut into 1.5- to 2-ounce pieces; make sure each piece has an "eye" in it. Store the freshly cut pieces at room temperature for 1 to 3 days, which cures the cut areas and makes them less susceptible to decay.

Fertilizing

Most vegetables require fertilizer for growth. Organic materials, such as manures and compost, and inorganic materials, such as chemicals, can be used to fertilize plants. Using both types of materials usually provides the best growth. Manures and compost can be used to increase soil fertility. They are usually applied at 1 pound per 4 or 5 square feet. These materials should be worked into the soil several weeks before planting in order to allow it to decompose. Manure that contains straw, sawdust, or similar materials should be applied with a commercial nitrogen fertilizer. Generally, if the soil has been properly amended with compost or manures or other organic materials, the only nutrient needed is nitrogen, if anything. Some commercial nitrogen fertilizers available are urea, ammonium sulfate, calcium nitrate, and ammonium nitrate. Apply these fertilizers at rates of 0.5 to 1 pound of nitrogen per 100 feet of row.

If manure and other organic material has not been used, apply fertilizer that contains both nitrogen and phosphorus before planting. All commercial fertilizers are labeled by the percentages of N-P-K; nitrogen (N), phosphorus (P), and potassium (K). Some common mixed fertilizers are 5-10-5, 5-10-10, 8-16-16, and 12-12-12. Apply these fertilizers at rates of 1 - 2 pounds per 100 feet of row. After plants are 3 to 4 inches tall, sidedress nitrogen in narrow bands or furrows and water thoroughly after application, or apply through the drip system. Consider light but frequent applications of nitrogen fertilizer every 3 to 4 weeks. Avoid letting the fertilizer come into contact with the plant stems to avoid burning.

Application tips

Inorganic fertilizers can be sidedressed. Manures are more difficult to use as a side dressing and must be tilled into the soil.

Banding: Make a small groove 1 to 2 inches deep on both shoulders of the bed, 4 to 6 inches from the plant row and band in the fertilizer. Replace the soil and irrigate.

Watering Potatoes

Examine your soil visually and with your hands to determine the need for additional water. Potatoes are shallow rooted and need light, frequent watering at least once a week with drip or furrow irrigation during the growing season to maintain uniform moisture content in the soil.

Proper irrigation will keep your plants vigorous. If soil is alternately wet and dry, the potatoes can become rough and knobby.

Pruning potatoes

Not much is required in terms of training or pruning your potatoes, but it is a good idea to pinch off any flowers that develop on the plant to favor tuber growth.

Harvesting and Storing PotatoES

Begin harvesting potatoes when they have reached the desired size. You can harvest a few at a time and keep the remainder in the ground until you are ready to eat them. When you "rob" potatoes, be careful not to damage the plant. Varieties grown for storage should be harvested when mature and the vines are dead. When the vines turn yellow, cut off the water and leave the potatoes in the ground for a few weeks to cure. Do not expose potatoes to sunlight as it will cause greening. The green portion is poisonous, bitter, and should not be eaten. Dig the potatoes up, allow them to dry, and store in a cool, dark location.