Knowing when to plant potatoes in zone 8 is the first step to a great harvest. This guide gives you the optimal planting time and simple steps for success.
Your zone 8 garden has a long, productive growing season. This is perfect for potatoes. But timing is still everything. Plant too early, and a late frost could damage your sprouts. Plant too late, and the summer heat will stop tuber growth before they get big.
Let’s break down the best dates, signs to watch for, and how to get your seed potatoes ready.
When To Plant Potatoes In Zone 8 – Optimal Planting Time Guide
For most of zone 8, the optimal planting window is from late January through mid-March. The exact best date in this range depends on your local weather and the type of potato you’re growing.
Potatoes are a cool-season crop. They grow best when the soil is cool at planting and when they mature before the peak of summer heat. The goal is to get them in the ground about 2-4 weeks before your last average spring frost date.
Understanding Your Zone 8 Frost Dates
Zone 8 is large, with varying last frost dates. Your specific location is key.
- Zone 8a: Last frost around March 15-30.
- Zone 8b: Last frost around March 1-15.
A good rule is to plant your potatoes when the soil temperature reaches at least 45°F (7°C). You can use a simple soil thermometer to check. If the soil is too cold and wet, seed potatoes may rot instead of sprout.
Signs Nature Gives You
Watch for natural cues. Many gardeners use phenology, which is observing plant and animal cycles. A traditional sign is to plant potatoes when the first dandelions bloom in your area. Another is when the soil is dry enough to work without clumping.
Planting for a Fall Harvest
You can also plant a second crop in late summer for a fall harvest. Aim for planting about 110 days before your first expected fall frost. For many in zone 8, this means planting in early to mid-August. The challenge here is providing enough water and shade to cool the soil for the initial growth.
How to Prepare Your Seed Potatoes
You shouldn’t plant potatoes from the grocery store. They are often treated to prevent sprouting. Buy certified disease-free seed potatoes from a garden center.
Here’s how to prepare them:
- Chitting (Pre-sprouting): Place your seed potatoes in a bright, cool (50-60°F) spot for 2-4 weeks before planting. This encourages strong, short sprouts.
- Cutting: Larger seed potatoes can be cut into pieces. Each piece should be about the size of a golf ball and have at least 1-2 “eyes” (sprout buds).
- Curing: Let the cut pieces dry for 1-2 days. This forms a callus over the cut surface, which helps prevent rot in the ground.
Step-by-Step Planting Guide
Follow these steps for planting your potatoes correctly.
1. Choose and Prepare the Site
Potatoes need full sun—at least 6 hours daily. The soil should be loose, well-draining, and slightly acidic (pH 5.0 to 6.5). Add compost or aged manure to improve soil structure. Avoid fresh manure, as it can cause scab disease on the tubers.
2. Planting Method
The trench-and-hill method is most common.
- Dig a trench about 6 inches deep.
- Place seed potato pieces cut-side down, 12 inches apart in the trench.
- Space trenches about 2-3 feet apart.
- Cover the potatoes with 4 inches of soil.
3. Hilling Up Soil
As the plants grow to about 6-8 inches tall, gently mound soil around the stems, leaving the top few leaves exposed. This is called “hilling.” It protects developing tubers from sunlight (which turns them green and toxic) and encourages more potatoes to form along the buried stem. Repeat hilling every few weeks.
4. Watering and Feeding
Keep soil consistently moist but not soggy. Uneven watering leads to misshapen tubers. A balanced fertilizer at planting and a side-dressing of a low-nitrogen fertilizer when hilling is usually sufficent. Too much nitrogen gives you lots of leaves but few potatoes.
Best Potato Varieties for Zone 8
Choosing the right type extends your harvest. Potatoes are catagorized by how long they take to mature.
- Early Season (70-90 days): ‘Yukon Gold’, ‘Red Norland’. Good for beating the heat and an early summer harvest.
- Mid-Season (90-110 days): ‘Kennebec’, ‘Purple Majesty’. A reliable main crop for zone 8.
- Late Season (110-135 days): ‘Russet Burbank’. These can be trickier in hotter parts of zone 8 but are possible with perfect timing.
Consider planting a mix of early and mid-season types to stagger your harvest and see what works best in your garden.
Common Problems and Solutions in Zone 8
Watch out for these issues common in our climate.
Pests
- Colorado Potato Beetle: Hand-pick orange larvae and adults. Use row covers.
- Aphids: Blast them off with water or use insecticidal soap.
Diseases
- Early/Late Blight: Promote air flow, water at the soil level, and rotate crops yearly. Don’t plant potatoes where tomatoes or peppers grew the previous year.
- Soil Rot: Ensure perfect drainage and avoid overwatering.
When and How to Harvest
For “new” potatoes, you can gently dig around plants about 2-3 weeks after they stop flowering. For your main harvest, wait until the plant vines have completely died back. This allows the potato skins to thicken for storage.
Use a garden fork carefully to avoid piercing tubers. Let potatoes cure on the soil surface for a few hours, then move them to a dark, cool, humid place for 1-2 weeks to further toughen the skin before long-term storage.
FAQ: Planting Potatoes in Zone 8
Can I plant potatoes in February in zone 8?
Yes, February is often an ideal month for planting potatoes in zone 8b and parts of 8a, provided the soil is workable and not frozen.
What happens if I plant potatoes too late?
Potatoes planted too late will try to form tubers in the peak summer heat. High soil temperatures above 80°F halt tuber growth, leading to a very small or non-existent harvest.
Can I grow potatoes from store-bought ones?
It’s not recommended. They may carry disease and are often treated with a sprout inhibitor. Certified seed potatoes are a safer, more reliable investment for your garden.
How often should you water potatoes?
Water deeply about 1-2 inches per week, increasing to 2 inches during hot, dry spells and when tubers are forming. Consistent moisture is crucial.
Is it to late to plant potatoes in April?
For a spring planting, April is generally too late for most of zone 8. The heat will arrive before the tubers fully develop. However, you can use that time to prepare for a successful fall potato crop instead.
By following this optimal planting time guide for zone 8, you give your potatoes the best start. Remember the key dates: late winter to early spring, and again in late summer for a fall crop. With proper planting, hilling, and care, you’ll be rewarded with a homegrown harvest that’s well worth the effort.