Potato Anatomy
Potato plants consist of roots, stems, flowers and leaves. The tubers are actually swollen portions of the underground stem. Potatoes produce flowers in varying shades of blue, purple and white, which are usually self-pollinated. The flowers may produce small berries that contain seeds. Both tubers and these true seeds can be planted to grow more potatoes – the techniques are very different.
Growing from Tubers
Any gardener who’s ever left a potato in the ground when harvesting has seen new plants grow from those missed tubers. The starch in the potato provides food for sprouts that develop from the indentations or eyes of the potato. You can grow more potatoes from certified disease-free “seed” potatoes or from your own stock. If you choose the latter, make sure to rotate the crop and choose healthy tubers.
Finding Seed
You can purchase what is called true potato seed, or TPS, from specialty nurseries and online sources. The seeds resemble those of tomatoes, to which the potato plant is related. Few of the common commercial potato varieties will produce seed, or if they do it’s often sterile or very hard to germinate. TPS is often available from rare and unusual varieties, however.
Collecting Your Own Seed
After the berries develop from the fertilized flowers and are fully colored, collect and gently mash the berries. Place the mashed berries in water and let them ferment for several days. Pour off the debris on top – viable seeds will sink. Rinse the seeds, dry well on paper towels and store in a cool, dry place. Potato seeds will often remain viable for up to 10 years.
Growing from Seed
Growing potatoes from seed is no more difficult than growing your own tomato seeds.
- Sow TPS no earlier than six to eight weeks before you last expected frost.
- Press seeds gently into potting soil and cover with 1/8th inch of soil.
- Water well with room temperature water.
- Keep temperatures between 55°F (13°C) and 65°F (18°C).
- Keep under full-spectrum grow lights 14 to 16 hours a day.
Potato Growing Basics
Potatoes prefer a rich, acidic soil. Amendments such as well-rotted leaves, aged manure and organic compost help ensure fertility and promote drainage. Coarse sand also improves drainage, which helps prevent fungus diseases and rot. Potatoes need plenty of water while growing but the soil should never be soggy. Always grow potatoes in full sun and keep well-weeded.
