Growing Potatoes
Potatoes and tomatoes are in the nightshade family. Both potatoes and tomatoes can be determinate or indeterminate. In this blog, learn all about growing abundant potato crops.
Potato Growing Method
Determinate potato varieties grow as a compact, bush-like plant and reach a fixed mature size. They produce tubers in a single layer at a fixed point along the stem, just below the soil surface. They are often referred to as "early" or "mid-season" potatoes, typically maturing in 70 to 90 days. They require minimal hilling (adding soil as they grow). While light mounding is recommended to prevent the tubers from turning green due to sunlight exposure, it will not increase the overall yield. No matter how carefully you add stacked layers, determinate potatoes will not take full advantage of the stacked growing space and will have lower yields.
Indeterminate potato varieties are larger, sprawling plants that continue to grow and produce tubers along the length of their stems throughout the season. They need a “stacked grow tower” to accommodate their much larger yield. They require a longer season (110–135 days) and must be continually hilled with soil to cover new leaves or maximum production. Magic Molly purple fingerling potatoes are the Deep Roots favorite indeterminate variety.
Simple growing method for determinate potatoes
A simpler version of this method can be done without a tower. Place four seed potato pieces directly on bare soil in a loose cluster about two feet wide, then cover them with eight inches of loose straw. When the shoots grow eight to ten inches tall, add more straw over the stems, leaving only a few inches exposed. Repeat this several times through the season until the mound is about two and a half feet tall. At harvest, pull the straw apart by hand and gather the potatoes. This no-dig version may produce less than the compost-filled wire tower, but it is inexpensive, simple, and beginner-friendly.
Build a tower for indeterminate potatoes
This stacked vertical growing technique in a DIY tower designed for late-season indeterminate potatoes. Instead of planting potatoes in long rows, this method grows them upward in a wire tower or straw mound. The purpose is to keep burying the potato stems as they grow, giving the plant more covered stem area where stolons can form. Since potatoes grow from underground stems rather than true roots, this repeated covering can encourage tubers to develop at multiple levels inside the tower.
Start by choosing the right potato variety. This method works best with late-season indeterminate potatoes such as Russet Burbank, Kennebec, Elba, or German Butterball. Avoid determinate varieties like Yukon Gold, Red Norland, and most fingerlings, because they usually set their tubers in one layer near the base of the plant.
Choose a sunny location that receives at least six to eight hours of direct sunlight each day. Potatoes need strong sun to produce healthy foliage and support tuber development. For gardeners in zones 5 through 7, planting is usually done two to three weeks after the last frost, once the soil temperature has reached about 45°F.
To build the tower cut a piece of welded wire fencing (24 to 30 inches wide) to about twelve and a half feet long. Use fencing with 2-by-4-inch openings. Deep Roots prefers the green wire fencing. Bend the fencing into a cylinder about four feet in diameter and secure the ends with wire ties. This creates a compact growing space with a footprint of about four square feet.
Mix the soil blend. Potatoes need loose, fertile, well-drained soil. Hard, compact soil leads to misshapen potatoes, and potatoes need uniform moisture while tubers develop. Blend a loose potato soil mix:
50% high-quality low-nutrient potting soil
30% Deep Roots high-nutrient compost
20% Deep Roots dense leaf mulch
Blend in potassium fertilizer. Mix in a organic potassium source like Kelp Meal or “Sulfate of Potash” into your lower soil layer to ensure the tubers have food to bulk up later in the season. For a 30-inch diameter grow tower, mix in 1 to 2 cups of kelp meal total. Avoid leaving dense clumps of kelp meal, which can occasionally lock up moisture or concentrate salt.Potatoes grow upward; as you hill them or as they grow up the tower, the main root system remains anchored at the bottom, pulling up the water and heavy potassium needed for tuber growth. The potato roots will actively search for potassium during the mid-to-late summer bulking phase.
Combine straw and soil mix: Combine equal parts chopped straw and your loose fertilized soil blend. This gives the seed potatoes a light, fertile base that drains well while still holding moisture. Use this mix to cover the plant as it grows through the season,
Prepare certified seed potatoes in 2 stages.
Chitting: About 5 to 10 days before planting put seed potatoes in a bright room with indirect light. Let them form short, sturdy green sprouts. This is called green sprouting or “chitting.” Do not let them grow long, pale, fragile sprouts.
Callus the cut potatoes: (Also called “scabbing over”) One to three days before planting leave very small seed potatoes whole. Cut larger seed potatoes into chunks. Make sure every piece has at least one strong eye; two or three is better. Place cut pieces in a single layer at room temperature until the cut surface dries and forms a protective callus. This step helps reduce the risk of rotting once the seed pieces are planted.
Start Your Tower
Line tower with straw and full with half the loose growing mix. Line the inside bottom twelve inches of the tower with straw, pressing it against the wire sides to keep the growing material from falling out. Add a 6-inch layer of soil first. The other 6 inches come later.
Place 10 to 15 seed potato cut-pieces on top of the first 6” of the soil & straw combo with the eyes facing upward. 10 pieces spread further apart will produce larger potatoes. Space them evenly around the tower.
Add second layer of soil and water. Cover them with another six inches of soil and straw combo, and water thoroughly. The tower should be evenly moist but not waterlogged.
Add more soil and straw. Within one to two weeks, green shoots should begin to emerge, depending on the soil temperature. Once the shoots reach eight to ten inches above the surface, add another four to six inches of compost and straw around the stems. Cover most of the new growth, leaving only the top three to four inches of foliage exposed. This is the heart of the method: each new layer buries more stem, encouraging the plant to produce more “stolons” (underground branches) in the dark, covered growing medium.
Continue this stacking process throughout the early growing season. Every time the shoots grow another eight to ten inches above the current surface, add another layer of compost and straw, again leaving only a few inches of green foliage exposed. Most towers are filled through three to four additional layering cycles, usually every two to three weeks, until the tower reaches about three feet tall.
Watering is especially important with this method. A wire tower filled with straw and compost dries out faster than potatoes grown in the ground because air moves around the sides. Check moisture by pushing your finger about three inches into the growing mix. If it feels dry at that depth, water deeply until moisture comes out of the bottom of the tower. In hot summer weather, this may be needed every other day. In cooler or rainy weather, twice a week may be enough.
Flowering
Stop adding new layers when flowering begins. Flowering signals that tuber formation is already underway, and the plant should now focus its energy on swelling the potatoes it has set.
Continue watering evenly, but do not keep burying the stems after this point.
After flowering, allow the plants to grow for another four to six weeks, or until the vines begin to yellow and die back naturally. This waiting period allows the potatoes to gain size and helps the skins toughen for better storage. Avoid harvesting too early, since the final weeks can add meaningful weight to the crop.
Harvest
To harvest, cut the wire ties and unwrap the fencing. The column of straw, compost, and potatoes will collapse onto the ground. Pull the loose material apart by hand and collect the potatoes from each layer. A well-managed first-year tower using the right variety, full sun, and steady watering may produce about forty to sixty pounds from one four-square-foot tower.
Pest and disease watch
Check leaves at least twice a week. Watch for Colorado potato beetle eggs and larvae, Flea beetle feeding, Leafhopper damage, Yellowing, spotting, or early die-back, and chewed stems near soil level.
Pest prevention steps are:
Use certified seed potatoes.
Start with fresh clean soil mix.
Do not reuse potato/tomato soil from a diseased crop.
Keep foliage dry when possible.
Remove badly diseased leaves.
Do not compost diseased potato vines.