How to Grow Potatoes
Many varieties of potatoes, as well as sweet potatoes and yams can be grown in backyard vegetable gardens. Potatoes are aggressively rooting plants, and require full sun to grow. They will produce the best crop when planted in a light, loose, well-drained but moisture retentive soil.
Planting can commence as soon as the ground can be worked in the early spring. Potato plants are generally not sold in nurseries. Unlike most other vegetables, Potatoes and Sweet potatoes aren't started by seed , they're started from Seed potatoes or "slips". Slips are shoots that are grown from a mature tuber. Seed potatoes from a catalog either online or print are generally the best way to go, as supermarket potatoes are treated with a chemical growth inhibitor to prevent sprouting. If you buy a potato from the store, be sure to find out if you're getting a bush type or a vining type.
Seed potatoes can be planted whole or cut into halves, or, quarters on larger varieties, with each piece containing an eye or two.
Seed potato contains buds or "eyes" which sprout and grow into plants. The seed piece provides food for the plant until it develops a root system.
Too small of a seed piece will produce a weak plant. They should be cut into pieces which weigh about 1 1/2 to 2 ounces each.
1. Supermarket potatoes shouldn't be used, they are usually treated with chemicals that permanently inhibit sprouting
2. Certified seed is not 100% guaranteed to be disease free, but has a lower percentage of disease.
3. It is advisable to purchase seed potatoes 2 to 3 weeks before planting so you can dry and sprout them.
4. Place the seed potatoes one layer deep in a sunlit warm area (70OF)
5. Turn the potatoes to "green" the skin's surface. 1/4 to 1/2 inch sprouts and buds should form on your spuds.
6. Seed potatoes are size coded. B-sized tubers weigh only an ounce or two and do not require cutting. Larger sizes do.
Your seed piece should weigh between 1 1/2 to 2 ounces and have at least two buds on it.
7. Make the first cut lengthwise in order to divide the cluster of buds at the end of the potato.
Smaller-sized pieces generally mean weaker plants .
8. Every pound of seed potatoes will contain as many as ten seed pieces.
9. Store the cut pieces for up to a week , but a least a full day before planting the to allow a dry callus to form, this will minimize the chances of rot.
10. Pieces should be stored at room temperature (65 to 70OF) in a well ventilated humid area .
11. A cardboard box with ventilation holes is just fine to store cut pieces. Do not store them in an airtight container
Potato Planting Methods
Now that your seed potatoes are properly prepared, you're ready to plant . There are several successful popular methods, No matter which method you use , be sure the soil is loose - not compacted which will inhibit development of the tubers.
A traditional potato planting method involves digging a shallow trench, and placing the seed potatoes in the trench, eyes facing up. This is the method I personally use and have had success with. Dig into the soil to a depth of 10-12 inches and be sure to remove rocks and other debris that could obstruct the tubers as they grow.
Work in plenty of compost to ensure the right soil texture, but be sure to avoid adding manure which can cause a disease called scab.
Till the soil 6 to 8 inches deep .
Potatoes should be planted in furrows at a depth of about 2 to 4 inches. Shallow plantings will encourage a faster emergence. Deeper plantings are advisable in dry / sandy soils.
Plant the cut side down with the eyes pointing up. Rows should be slightly mounded to allow water to drain from the seed pieces and reduce decay.
To protect from late frost a temporary covering of straw or appropriate mulch is advisable.
Note : To over-till is to over-kill, it can cause the soil to seal over and lead to seed suffocation.
The soil should be evenly moist, but not wet or soggy. If the soil is waterlogged when you dig, your seed potatoes will probably rot before they grow.
Potatoes are a hardy crop and can tolerate climatic aberrations, light frost etc.., but you should still provide some frost-protection for the young plants. A temporary ground cover (ventilated), or mulch.
The container method optimizes your use of space. Plant your seed potatoes in the bottom of a tall container, such as a non metallic garbage can or barrel with holes in the base for drainage.
In the container bottom put a layer of shredded newspaper.
The newspaper will keep the soil on top of this moist and keep much of the soil from oozing out of the drain holes.
Put 6" -8" of soil in the container bottom
Evenly spread out your seed potatoes on top of the soil.
Put another inch or so of soil on top of the seed potatoes.
Add more soil as the plants grow.
Some gardeners simply lay their seed potatoes on top of the soil and then cover them with a several inches of mulch.Additional mulch is added as the plants grow. Personally, I don't care for this method as it tends to attract rodents, as well as insect pests in warmer weather and possibly rots as well.
Make sure you keep potatoes well-covered. If the tubers are exposed to sunlight while they're growing, they'll develop solanine, a bitter, toxic alkaloid that imparts a greenish tinge. See: Are Green Potatoes Safe to Eat ?
Companion Planting Potatoes
Potatoes do well in proximity of Beans, Cucumber, Corn, Kohlrabi, Parsnip, Pumpkin, Rutabaga, Squash family, Sunflower, Turnip, Fennel. Horseradish, planted at the edges of the potato patch will provide protection against some insect scourges, as will Marigolds
The sweet alyssum has tiny flowers that attract beneficial insects, such as predatory wasps. Plant sweet alyssum alongside potatoes, or let it spread to form a living ground cover.
Do not plant near to or in succession with Eggplants - Tomato - Strawberries - Pumpkins - Squash - Sunflowers - Cucumbers and similar circubits
They carry and transmit the same blights and will infect one another. See - Potato Plant Companions
Water, prior to and after planting should be applied . Do not water excessively as this can promote root rots and fungus in potatoes. Drip irrigation provides the plants with a more uniform application of water, placing it near the root zone and using less water. Drip irrigation also minimizes the amount of foliage and fruit disease compared with overhead irrigation . Inexpensive water timers are available
When setting out seed potatoes, apply a common starter solution .Soil for potatoes should be high in phosphorus and potassium and very low in nitrogen , as nitrogen encourages foliage growth at the expense of the tubers. 6-24-24, or 8-24-24 are preferable. If you don't know what these numbers mean See Fertilizer
Compost or Peat moss mixed in the soil for drainage is also advisable.If your soil is very heavy, growing your potatoes in raised beds can help. Soil ph should be 4.5 - 6.0. See also Tracking and Adjusting Soil pH
Harvesting and Storage
When you believe that you have early potatoes big enough to eat, dig gently into your early hills, feel for the best-sized potatoes and ease them out. The plants will keep on growing and producing as long as you are gentle and don't cause extensive root damage in this early harvest. During seasons when the soil has been unusually moist, hunting for early potatoes by hand becomes more difficult.
You can dig up entire plants, harvest the young spuds you find and put the plants back in the ground. They will survive this rude transplant and continue to produce more potatoes. But working fast is important; freshly dug potatoes shouldn't stay in the sun very long.
In North regions [Zones 2-5 -See Frost Dates] , harvest the bulk of your potato crop in September, when the plant tops are dying and the days are getting cooler .Choose a warm, dry day after a period of little or no rain. Cloudy days are even better, since too much light turns newly dug potatoes green, changing their flavor. Be gentle... it is their first time. Do not rough up or bump the potatoes. Each bruise lowers the storage quality of the potato.
When potatoes are exposed to light their skins turn slightly green , this is caused by a toxin called solanine. Solanine develops if potatoes aren't fully covered by soil while growing, or if you leave them in the sun too long after the harvest, or aren't stored in complete darkness.
Because solanine is slightly toxic, it's possible to get sick if you consume a large enough helping of greened potatoes. Peeling or cutting away green sections before cooking usually eliminates the problem, as most of the solanine is located in the potatoes skin.