5 Signs It’s Time to Hill Your Potatoes
Hilling is a simple process that leads to higher potato yields. You can double your harvests with a little extra soil and labor! Watch for these five common signs that your potatoes need hilling from seasoned grower Jerad Bryant.
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Potato hilling is a relatively straightforward process. As the green, leafy shoots grow aboveground, you’ll cover them with extra soil or mulch. Covering them encourages lateral side shoot development, which increases the amount of tubers that will form later in the growing season.
The hilling method is why many potato farmers grow their crops in trenches. As the stems grow, they add soil to the trench to continuously cover them up. New shoots and roots grow, which later develop into full-sized tubers.
You don’t need to be a potato farmer to hill your potatoes! And you should only hill them once if you’re growing a determinate potato variety. For those that need hilling, simply cover them up as they grow with whatever materials you have on hand. Compost, leaf mold, and straw are other good materials for covering the tubers.
5 Signs It’s Time to Hill Potatoes
Without further ado, here are five signs it’s time to hill your potatoes. Grab a bucket full of soil or mulch, put on your garden shoes, and get ready to take care of your taters!
Warming Weather
The days lengthen and warm as winter turns to spring, and spring to summer. Warming weather triggers ample stem and root growth from potatoes. As their aboveground shoots grow, they’ll require hilling to promote more root development underground.
Wait for the leafy shoots to emerge before starting the hilling process. Don’t hill prematurely, as it’ll create a thick soil layer that the stems must push through. You want soft, moist soil free of chunks and dense clumps.
Though warm weather is a sign you should hill, it’s not the only sign. Pay close attention to the leafy shoots to know when it’s best to do so. They’ll sprout in late winter and early spring when lilacs and flowering cherry trees bloom.
Shoots are Long and Leggy
Long, leggy shoots without ample leaves are the perfect candidates for this technique. Cover them with soil or mulch so they sprout dozens of new roots that, in late summer, grow into new tubers. Without covering, they may flop over and develop a poor harvest.
If you’re growing potatoes in grow bags or containers, consider placing the pots on their sides. This will allow you to cover up the growing stems without soil spilling out of the container. It requires more space, but it’ll lead to significantly higher yields.
Or, you can plant potatoes in a pot and continuously fill it with soil as the stems grow. Use a large 10 or 15-gallon container, and add a few inches of soil every week or two until flowers appear.
Heaving Ground
When tuberous potatoes form from the roots of the plants, they push the soil upward during the process. You’ll see the ground heave upward late in the growing season. Cracks may appear on the ground, and potted specimens may have soil fall over their edges.
If the ground is heaving upward, add dirt or compost near the stems of your potatoes. Cover a few inches of the lower stems, and fill any forming cracks with more soil.
Heaving ground is one of the most apparent signs that your potatoes require hilling. As the growing season progresses, the tubers may need two or three more hilling periods until mid to late summer.
You See Tubers
Alongside the heaving ground, you may see tubers forming on the soil’s surface! Though this is a good sign that you have a healthy crop forming, the potatoes may turn green if they receive sunlight. Light causes potatoes to turn green and develop a poisonous substance, solanine.
Hilling is the best way to discourage the greening process and poisonous solanine. Cover your potato crop with mulch as the tubers appear on the ground; they’ll form near the stems aboveground. Keep the site moist, and water it well after adding more mulch or dirt.
Always avoid eating green potatoes. They’re unfit for consumption, but you can plant them as seed pieces in early spring or midsummer for a fall crop.
Flower Buds Appear
Flowers appearing may or may not be a good sign that it’s time to hill—it all depends on how many times you’ve hilled in the past. If you’ve been diligent with hilling and have covered the stems frequently, you may do one last covering as the flowers open.
If you haven’t hilled at all and the stems are long, floppy, and dense with leaves, it may not be a good idea to add soil around the stems. Potato flowers appearing is a sign that tubers are forming. The aboveground stems will begin yellowing and dying back, and they won’t develop new roots if you bury them.
Fun fact: if you collect the potato fruits that form from the flowers, you can harvest seeds and try sprouting them! Potato seeds develop new traits when the seedlings sprout; you may discover a new variety if you grow them to maturity. Like green tubers, the fruits are poisonous. Never eat them, and use them solely for collecting seeds.
Key Takeaways
- You may hill these tuberous vegetables from early spring through midsummer, or midsummer to early autumn when planting a fall crop.
- Watch for heaving ground, as it’s the main sign that it’s time to hill your crop.
- Use a nutrient-rich mulch or potting soil to hill these tuberous veggies. Compost is ideal.
- It’s too late to hill potatoes if their stems have flowered and are dying back.
- Green potatoes and fruits are poisonous; use them for growing new plants and never for eating.
Frequently Asked Questions
Can you hill potatoes after they flower?
It’s not a good idea to do that. The stems will begin dying back, and they won’t form roots if you cover them after the flowering period.
When should you hill potatoes in containers, grow bags, or raised beds?
You may hill them anytime after they’ve grown long, thick stems aboveground. Leave some leafy portions aboveground, and cover the leafless lower stems.
Can you hill potatoes with leaves?
You can, though they may rot if the leaves form a layer that’s too thick. Consider composting the leaves first to form leaf mold to hill with, or use compost, straw, or potting soil.
