I recently did a search on Google and found a website that listed 132 species of potatoes. Another website said that hundreds of different varieties are grown around the world. The various kinds of potatoes do best at different altitudes, have different textures and flavors, and prefer different types of climates. So how do you figure out what grows best in your garden here in
To answer that question, Napa County Master Gardeners do field tests. Each year, we test a different type of vegetable to find out which variety does best in our climate and soil.
This year, we tested three kinds of fingerling potatoes. Fingerling potatoes are elongated and relatively narrow in diameter. However, as we can attest from the trials, they can be as small as an inch across, or as long as six inches and two inches in diameter. We tested Banana (yellow), Rose Finn Apple (yellow-pink), and Purple Peruvian. They're all long-season potatoes that require approximately 120 days from planting to harvest.
Our trials follow scientific protocol. We test five replications (sets of the three varieties), and we randomize the location of each variety within each replication. Some Master Gardeners planted their potatoes in the ground, some in containers, and some in a type of raised bed. We allowed four square feet of space for each plant.
We bought high-quality seed potatoes from a company that specializes in them. Almost every potato sprouted. Then we had to start "hilling up." Potatoes are actually part of the stems of potato plants, not part of the roots. But they only grow on stems that are underground.
Hilling up means that you are covering a part of the above-ground plant, so that more potatoes can grow on the stems that you are covering. Most Master Gardeners hilled up two to three times, using garden soil, compost or straw. This was a lot easier for those folks who planted in containers as they had a lot less material to move.
Some gardeners had to withdraw from the trials. Gophers and deer had found their plantings, and although the critters rarely demolished all the plants, they rendered the data from those gardens useless. The plants did survive attacks by some other pests, including tomato hornworm.
At harvest time, a new challenge arose: moving all that soil (or compost) and, in the case of the Purple Peruvians, finding the potatoes. (Boy, did they blend in well!) Again, the container folks had an advantage: they could simply turn over their containers and find the potatoes that way. The rest of us had to use our spading fork and carefully move the soil aside. This chore took several hours and was definitely everyone's least favorite task.
It's best to wait two weeks after the vines die back naturally to harvest the potatoes. During this time, the potato skins toughen up a little in the ground. They'll store better, and you're less likely to damage the skin when you dig them up.
We had no idea how much our plants might produce. The total harvest weight per garden ranged from 3 pounds (in an area with little water) to 75 pounds (about 5 pounds per plant).
Based on the results from the 15 Master Gardeners who were successful, the Banana fingerling potato had a higher yield than the Rose Finn Apple and the Purple Peruvian. All three varieties did well, but our observation suggested that the Banana variety was the most vigorous.
We can confirm that potatoes succeed in a lot of
They grow as well in containers (as long as the containers are at least two feet wide and two feet deep) as in the ground, and you can "hill up" with almost any type of material. The lighter the material, the easier it will be to dig the potatoes at harvest time.
We all agreed that homegrown potatoes taste much better than those bought in the store. We didn't expect to taste much difference but were pleasantly surprised. Most of us enjoyed this field trial so much that we're planning to plant potatoes next year.