Knowing when to plant potatoes in Utah is the first step to a successful harvest. Getting the timing right means your spuds will grow strong and produce plenty of tubers for you to enjoy later.
Utah’s climate varies a lot, from the cold mountain valleys to the warmer desert basins. This means planting time isn’t the same everywhere. But don’t worry, a simple rule and some local knowledge will set you on the right path.
When to Plant Potatoes in Utah
The classic guideline for planting potatoes is to get them in the ground 2-4 weeks before your last expected spring frost. For much of Utah, especially the populated Wasatch Front, this window typically falls from late March through mid-April.
Potatoes can handle a light frost and even prefer to start in cool soil. Planting too early in cold, wet ground can cause them to rot. Planting too late exposes the plants to Utah’s intense summer heat too soon, which can halt tuber growth.
Utah Planting Zones and Dates
Here’s a more detailed breakdown by general area. Remember, microclimates in your own yard can make a difference!
- Northern Utah & Mountain Valleys (Zones 5-6): These areas, like Logan or Heber City, have a shorter growing season. Aim for mid-April to early May. Wait until the soil is workable and not frozen.
- Wasatch Front (Zones 6-7): This includes Salt Lake City, Provo, and Ogden. Your optimal planting time is usually early April to late April. The soil warms up just enough here.
- Southern Utah (Zones 7-8): Warmer areas like St. George or Moab can start earlier, often in late February or March. The key is to avoid the peak summer heat, so getting them in early is crucial.
How to Use Soil Temperature as Your Guide
The most reliable method is to check your soil temperature. You can use a simple soil thermometer from any garden store.
Potato seed pieces sprout best when the soil at planting depth (about 4 inches) is consistently at least 45°F (7°C). A ideal range is between 50°F and 65°F. If the soil is too cold, your seed potatoes will just sit there and may decay.
Preparing Your Potato Seed and Garden Bed
Choosing the right seed potatoes is vital. Always buy certified disease-free seed potatoes from a garden center. Do not use potatoes from the grocery store, as they are often treated to prevent sprouting and can carry disease.
Chitting (Pre-Sprouting) Your Potatoes
About 2-3 weeks before your planned planting date, you can encourage growth by pre-sprouting. This gives your potatoes a head start.
- Place your seed potatoes in a single layer in a cool, bright room (not direct sun).
- Let the eyes develop short, sturdy green sprouts about 1/4 to 1/2 inch long.
- If a potato is large, you can cut it into pieces a day or two before planting. Ensure each piece has at least 1-2 strong sprouts.
Preparing the Soil
Potatoes need loose, well-draining soil. They thrive in slightly acidic soil with a pH of 5.0 to 6.5.
- Choose a spot that gets full sun (at least 6-8 hours).
- Loosen the soil deeply, about 12 inches down, to give the roots and tubers room to expand.
- Mix in several inches of compost or well-rotted manure. Avoid fresh manure, as it can promote scab disease on the potato skins.
The Step-by-Step Planting Process
Once your soil is ready and your seed potatoes are prepped, it’s time to plant. Follow these steps for the best results.
- Dig Trenches: Dig straight trenches about 6-8 inches deep and space them 2.5 to 3 feet apart. This spacing is important for hilling later.
- Place Seed Pieces: Place your seed potato pieces in the trench with the sprouts facing upward. Space them about 12 inches apart within the row.
- Cover Gently: Cover the seed pieces with 3-4 inches of soil. Do not pack it down tightly; keep it loose for the sprouts to push through.
- Water Well: Give the newly planted area a thorough watering to settle the soil around the seed.
The Importance of Hilling
Hilling is the secret to a great potato harvest. It protects developing tubers from sunlight (which turns them green and toxic) and encourages the plant to produce more potatoes along the buried stem.
- When the green plants are about 6-8 inches tall, use a hoe to gently mound soil from around the plant up around the stem, covering about half of it.
- Repeat this process every few weeks as the plants continue to grow. Leave a few inches of leafy growth exposed each time.
- Continue hilling until the plants begin to flower. By then, you should have a nice, large mound around each plant.
Caring for Your Growing Potato Plants
Consistent care throughout the season will ensure healthy plants and a bumper crop.
Watering and Feeding
Potatoes need consistent moisture, especially once they start forming tubers. Aim for about 1-2 inches of water per week, including rainfall.
Water deeply and less frequently to encourage deep roots. Reduce watering when the foliage starts to yellow and die back near harvest time, as this helps cure the potatoes.
A balanced, low-nitrogen fertilizer at planting is good. Too much nitrogen will give you lots of leaves but few potatoes. Side-dressing with compost when you hill is a great natural option.
Pest and Problem Watch
Keep an eye out for common Utah potato pests. The Colorado potato beetle is a major one. Hand-pick the orange larvae and adults off plants and drop them in soapy water.
Aphids can also be a problem. A strong spray of water from the hose can often dislodge them. Rotating where you plant your potatoes each year helps prevent soil-borne diseases.
Harvesting Your Utah Potatoes
You can harvest “new” potatoes about 2-3 weeks after the plants finish flowering. Gently dig around the edges of the mound with your hands to find a few tender spuds.
For main crop potatoes for storage, wait until the plant foliage has completely died back and turned brown. This usually happens in late summer or early fall in Utah.
Use a digging fork to carefully loosen the soil beside the hill and lift the potatoes. Let them cure on the soil surface for a few hours, then brush off dirt and store in a cool, dark, and humid place.
FAQ: Planting Potatoes in Utah
Can I plant potatoes in July in Utah?
In most of Utah, July is too late for a traditional spring planting. The heat will stress the plants. However, you can plant in mid to late summer for a fall harvest in some warmer areas, aiming for about 90 days before your first fall frost.
What are the best potato varieties for Utah?
Many varieties do well! For early harvest, try ‘Yukon Gold’ or ‘Red Norland’. For storage, ‘Russet Burbank’ (the classic baking potato) and ‘Kennebec’ are excellent choices that adapt well to Utah’s conditions.
How deep should I plant potato pieces?
Plant them about 4 inches deep initially. Remember, you will be adding more soil through hilling as they grow, which effectively plants them deeper over time.
Can I grow potatoes in a container in Utah?
Absolutely. Use a large container (like a 15-gallon pot) with drainage holes. Fill it partway with soil, plant your seed pieces, and continue to add soil as the plants grow, just like hilling. This is a great option for small spaces or poor soil.
Getting your potato planting timing correct in Utah makes all the difference. By following these local guidelines and paying attention to your soil, you’ll be well on your way to enjoying homegrown potatoes from your own garden.