The following is a list of hints that may prove useful in growing your potatoes and may answer some questions that you have.
FERTILIZATION AND SOIL PREPARATION
Regardless of whether you are growing your potatoes naturally or conventionally, fertilization and soil preparation is very important. The soil should be moist so that it works easily. Whatever your choice of fertilizer might be, you should apply as evenly as possible to the top of the soil. After doing this you can work the soil with whatever means that you have, from a garden spade to a rototiller. Soil should be worked until it's as loose as possible and all of your fertilizer has been incorporated. Prepared soil depths may vary but I suggest having at least 8" of loose soil to work with.
SEED PREPARATION AND PLANTING
Depending on when you wish to plant, I suggest the following;
My rule of thumb is that for each pound of seed that you plant you will get from 6 to 8 plants, and from this pound of seed you can figure on about 10 pounds of potatoes in return. This will vary greatly depending on your conditions. If your seed is already sprouted, you can cut it into the desired seed size, I like my seed pieces not less than 1 oz each and 2 oz is better. Any potato weighing less that 1 and 1/2 ounce should be planted whole. If your seed is not sprouted when you receive it and you have 2 to 3 weeks before you're ready to plant, my suggestions are to take the seed and put it in a warm sunny area and let it sit there and break dormancy. When the sprouts are about 1/4 inch long and hard and green they are ready to plant.
A day or two before planting cut the seed into the desired size, making sure that there is at least one eye on each piece, and let them cure before planting. If you are using seed treat you can cut and plant right away.
I suggest that you plant the seed about 2 inches deep and cover with about one inch of soil. By doing this your potatoes will come up quicker and begin making your crop instead of laying in the ground and slowly coming thru.
When the plants are about 3 inches tall take the soil from around the plants and pull it up under each plant. Continue doing this each week, until you have made a hill that is from 5 to 8 inches tall. This provides a good area for the tubers to develop in soft soil and helps prevent the new potatoes from getting green. During this time keep the soil moist but DO NOT OVER WATER. After the plants are about 12 to 14 inches tall you can water them more and soak them, however after doing so allow the soil to dry so that it is still damp to the touch. Depending on your area you may only need to water your potatoes once a week. Remember the lighter your soil the more often you will need to water and the heavier the soil the longer is will hold the moisture. Sand dries out much quicker that heavy clay. I strongly advise that you add additional fertilizer at least once during the growing season and probably twice is better. Just apply on the surface, on and around the plant, and water it into the soil. For conventional production I recommend Miracle Grow mixed and applied at the recommended rate.
About 3 weeks before harvest, reduce the amount of water to maybe half of your normal irrigation. This will help your potatoes to size.
THE HARVEST
You can begin to enjoy your crop at any size. If you want your plants to last and enjoy the potatoes at the same time, within about 2 months from planting, you can gently dig around the plant and remove the new potatoes to eat. If you are very careful not to disturb many of the roots your plant will set more tubers and you will have new potatoes all summer. If you are growing potatoes for storage then I recommend letting them grow full season. About 2 weeks before you want to harvest, cut the plants off at ground level and let the soil dry down. By doing this the potato skin will toughen and when you harvest them they will not skin or bruise.
STORAGE
If you can store your potatoes between 36 and 40 degrees in a dark place they will last several months.
IN CONCLUSION
If you have further questions please ask.....and enjoy your potato growing experience.