Can't Top These Tiny Taters!

Good things come in small packages, and that is certainly true of Baker Creek’s selection of microtuber seed potatoes! While we will continue to offer traditional seed potatoes, we have really come to appreciate the advantages of microtubers: their high quality yields, freedom from common diseases, and longer storage life. 

Any potato variety, including our heirloom and open-pollinated varieties, can be cultivated using tissue culture techniques. It seems impossible to get a crop of full-sized potatoes from these tiny tubers, but it happens!  It's not magic!

What is a Microtuber? 

Microtubers are seed potatoes grown in sterile conditions using tissue culture. They are not genetically modified organisms; tissue culture is a cultivation technique, not genetic manipulation. Their yield is virtually identical to a traditional seed potato, and microtubers will grow into full-size plants and tubers.

Sangre Potatoes with microtubers in foreground 

What are the Benefits of Microtubers over Traditional Seed Potatoes? 

Because they are grown in a sterile environment, using clean cultivation practices, microtubers are high quality, disease free, and have a longer storage life than traditional seed potatoes.  

“Because they’re virus free,” says Baker Creek Farm Manager Jordan Chell, “they’re very, very vigorous in their growth.”  

That vigor accounts for how a microtuber the diameter of a dime could yield nearly as much as a palm-size chunk of a seed potato. 

Russet Burbank Potatoes with microtuber shown

How Does Microtuber Production Work? 

Microtuber production involves virus remediation and micropropagation of plants, Jordan said, conducted in a 100 percent sterile environment. 

It is basically a two-step process of cultivating plant material and tubers in a clean, controlled environment. 

First, the meristematic tip of the plant is removed. Meristems are the most active growing part of the plant and are made of undifferentiated cells similar to stem cells in animals. These cells are then introduced into different plant hormone solutions that encourage plant growth. This process is repeated, taking cuttings and proliferating more plant material, until it is time to grow the tubers. There are a variety of methods for this, but it is often done in polybags using a liquid medium with sugars, hormones, and other nutrients to encourage growth. 

The first step is done in the light (16 hours a day for five to seven weeks). Then the growth medium is removed and replaced with a new growing medium, the lights are turned off, and the microtubers form in the dark. 

“You end up with all these little microtubers that you can harvest out of the bag,” Jordan said. 

Adirondack Blue microtubers with larger potatoes and ruler for scale

How Do I Grow Microtubers? 

Most potato varieties are indeterminate, and you can hill them to increase the tuber production. We offer two varieties that are determinate and don't need hilling. Determinate potatoes can have a smaller yield than the indeterminate varieties. 

If you receive your micro tubers before you are ready to plant, keep them in a paper bag somewhere cool. Don't let them freeze. 

Soil: The best soil for growing potatoes is fertile, loose, well-draining soil. Potatoes don't like wet soil and need loose soil for the tubers to grow large. 

Water: Potatoes need about 1-1/12 inches of water each week. 

To hill or not to hill: If you are growing an indeterminate variety, hill your potatoes when the top growth reaches a height of about 8-10 inches by burying the stems with soil or mulch, leaving about 4 inches of the plant exposed. This will induce the plant to set more tubers, increasing the yield. 

Are Microtuber Potatoes Grown Differently than Seed Potatoes?   

Since the plants will eventually end up approximately the same size, micro tubers are planted at the same spacing. They have the same light, water, and soil requirements. The only difference is the depth at which they must be planted; micro tubers are much smaller and therefore will be planted shallower than a seed potato. Micro tubers should be planted 2 inches deep, while seed potatoes should be planted 5-6 inches deep.  See our Seed Potato Growing Guide to learn more. In addition, you should leave the microtubers whole, unlike regular seed potatoes, which can be cut in pieces to propagate additional plants.

Yukon Gold potatoes with microtubers shown in front

Key Takeaways: 

• Microtubers are grown in a sterile environment from plant material that is disease free to produce disease-free tubers. 
• Microtubers are produced via tissue culture propagation. It is a technique, not genetic alteration. 
• Microtubers will produce regular-size plants and potatoes. 
• Microtuber cultivation is essentially the same as for other seed potatoes, except that they should be planted more shallowly than a seed potato – about two inches deep. 
• Plant microtuber seed potatoes whole; do not halve or quarter them before planting.

About the Author:

Horticulturist John Lenz in the garden

Visitors to Baker Creek’s Mansfield, MO, seed store may know John Lenz as an affable and loquacious storekeeper, but he is also a horticulture expert who oversaw our greenhouse program during a time of rapid expansion. He has a degree in horticulture from New Mexico State University and an MBA from St. Leo University in Florida.  Stop in and say hello if you are visiting our Mansfield, MO, location! 

You can always email your gardening questions to seeds@rareseeds.com. Put "hort question" in the subject line, and John or someone else on the horticulture team will get back to you.