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10. Starting Tubers

A tuber is usually a plant part that is underground, among the roots. A potato and a sweet potato are both tubers. A tuber has places on it that can spring to life as new plants. The eyes in the potato can sprout into new plants. You may have noticed a potato do this if it is stored in a room and can see some light.

Equipment required:

5 sweet potatoes

5 seed potatoes (not supermarket, available from a nursery or plant store)

1 tub grower with sawdust or peat moss.


Sweet Potatoes

Sweet potatoes grow best in soils with low nitrogen, or else they will run to vines.

Too much moisture rots the tubers. So the tubers are grown in bloom nutrient, which has a long nitrogen content.

The sweet potato sprouts are called slips. To produce slips lay the sweet potatoes on their sides in the sand for about a month. Cover the sweet potatoes with about 2 inches of sand make sure the sand is warm (about 75 to 85 degrees). Use two of the sweet potatoes to uncover and examine every few days.

When the sprouts form, twist them off and plant. The slips should be a few inches long, and have several leaves before being twisted from the tuber. Set the slip in about 6 inches deep, and leave two leaves aboveground. Plant the sprouts into a tub with sawdust or peat moss. (Potatoes like a more acid (5.0 to 6.0 pH) soil or media, so they grow better is sawdust or peat moss. They also should be grown in a media where the tubers are left in dark, and the media is soft enough to allow for reaching in, finding a big tuber and then harvesting it.)

Plant about one sprout per square foot. There may be extra slips that can be taken home by students.


1. Place a four whole potatoes 3" deep in a hydroponic tub with sand. Most potatoes sold in a supermarket can have diseases or have been treated so they will not sprout. Obtain potatoes from an organic garden, or "seed" potatoes from a nursery.

2. One potato can be cut into 4 or 5 pieces. If you are going to use cut pieces, lay out and allow the cut pieces to dry from 8 to 10 days. Then plant with the cut side down.

The potatoes are also placed about 2 inches deep in the sand. Small sprouts should begin to form on the potato. Use two of the potatoes to uncover and examine every few days.

  1. The potatoes do not have to be replanted. However, there may be many sprouts in the tub, and only four should remain in 2 square foor growing space. The others should be thinned and some can be taken home by students.

4. As the vines grow, mound up media around the bottom to make sure the growing potatoes stay dark. If a potato sees light it will start to turn green, which is poisonous.


5 New potatoes can be harvested when the vines blossom. Harvest by reaching in under the plant and finding a larger potato. Any green portions of potato should be cut away before cooking.

Hint: Potatoes will not form tubers when the media temperature is over 80 degrees.


Tuber worksheet

  1. What is a tuber?
  2. A tuber is a short think, fleshy underground stem of a plant that usually has buds or "eyes". The potato and the sweet potato are tubers.

  3. In soil, tubers will require about five months to grow. How fast do they grow in hydroponics?

Hydroponic potatoes should start to be harvested in about 2 months. The potatoes are harvested by reaching in and pulling a potato. One should be much bigger than the others. In potatoes are harvested every few days the plant may continue to produce potatoes.

Revised: 1 May 2016
Copyright © 2016 Institute for Simplified Hydroponics