Knowing when to plant potatoes in zone 8b is the first step to a successful harvest. This guide will give you the exact timing and tips you need for a bumper crop of spuds.
Gardening in zone 8b is a joy, with its long, mild growing seasons. But that mildness can make timing tricky. Plant too early, and a late frost might nip your sprouts. Plant too late, and the summer heat will bake your plants before they can produce.
Don’t worry, though. With a little planning, you can grow fantastic potatoes. Let’s get your planting schedule sorted.
When to Plant Potatoes in Zone 8b
For most of zone 8b, the optimal potato planting time is in late winter to early spring. You want to get them in the ground about 2-4 weeks before your last average spring frost date.
Since zone 8b last frost dates range from mid-March to early April, target these windows:
- Late February to Mid-March: This is your prime planting window for an early summer harvest.
- Late Summer (August): You can plant a second crop for a fall harvest, avoiding the peak summer heat.
Potatoes prefer cool soil to start their growth. A good rule of thumb is to plant when the soil temperature is consistently around 45-50°F. You can use a simple soil thermometer to check this.
Why Timing is So Critical
Getting your timing right solves two big problems. First, it helps your potatoes avoid a killing frost after they’ve sprouted. Second, it ensures the tubers develop before the soil gets too hot in summer.
Potato plants actually stop forming new tubers when soil temperatures climb above about 80°F. In zone 8b, getting your spring crop in early means they’ll be finishing up just as the weather gets seriously warm.
Signs Nature Gives You
Old-time gardeners often use natural cues. A classic one is to plant potatoes when the first dandelions start to bloom in your area. This is a handy, free signal that soil conditions are becoming favorable.
Preparing for Planting: Seed Potatoes and Soil
You can’t just plant potatoes from the grocery store. They’re often treated to prevent sprouting. Instead, buy certified disease-free “seed potatoes” from a garden center or reputable online supplier.
Choosing the Right Variety
Select varieties that suit your season and taste. For zone 8b’s spring planting, consider:
- Early Season (60-80 days): ‘Yukon Gold’, ‘Red Norland’, ‘Irish Cobbler’. Great for beating the heat.
- Mid-Season (80-90 days): ‘Kennebec’, ‘Viking Purple’. A reliable choice for good yields.
- Late Season (90+ days): ‘Russet Burbank’, ‘German Butterball’. Best for fall planting in our climate.
Chitting (Pre-Sprouting) Your Seed Potatoes
About 2-3 weeks before your planting date, start the chitting process. This gives your potatoes a head start.
- Place your seed potatoes in an egg carton or shallow box, with the “eyes” (little dimples) facing up.
- Leave them in a cool, bright room (not direct sun).
- Short, sturdy sprouts about ½-inch long will form. This is what you want.
Cutting and Curing Seed Potatoes
If your seed potatoes are larger than a golf ball, you can cut them to make more plants. Each piece should have at least 1-2 strong eyes or sprouts.
After cutting, let the pieces cure for 1-2 days. This allows the cut surface to dry and form a callus, which helps prevent rot once planted. Just leave them on a paper towel in a cool spot.
Preparing Your Garden Bed
Potatoes need loose, well-draining soil. They love slightly acidic soil with a pH between 5.0 and 6.0.
- Choose a spot that gets full sun (at least 6-8 hours).
- Loosen the soil deeply, about 12 inches down. Remove any rocks or clumps.
- Mix in several inches of compost or well-rotted manure. Avoid fresh manure, as it can cause scab disease on the potato skins.
The Step-by-Step Planting Process
1. Trench or Hole Method
The traditional way is to dig a trench about 6 inches deep. Space your seed potato pieces about 12 inches apart in the trench. If you’re planting multiple rows, space the rows about 2-3 feet apart.
Place each piece with the sprouts facing upward. Then, cover gently with 4 inches of soil. Leave the rest of the trench unfilled—you’ll fill it in later.
2. The “Hilling” Technique
Hilling is crucial. It protects developing tubers from sunlight (which turns them green and toxic) and encourages more potatoes to form along the buried stem.
- When your plants are about 6-8 inches tall, use a hoe to pull soil from between the rows up around the stems, leaving just the top few leaves exposed.
- Repeat this process every few weeks as the plants grow. You’ll end up with a nice mound or “hill” around each plant.
Caring for Your Growing Potatoes
Watering Needs
Potatoes need consistent moisture, especially once they start flowering (that’s when tubers are forming). Aim for about 1-2 inches of water per week.
Avoid letting the soil dry out completely, then flooding it. This inconsistent watering can cause misshapen tubers or a condition called hollow heart. Water deeply at the base of the plants, not the foliage, to help prevent disease.
Fertilizing Schedule
They are moderate feeders. Too much nitrogen will give you lots of leaves but few potatoes.
- At Planting: Use a balanced, low-nitrogen fertilizer or one formulated for potatoes mixed into the soil.
- Mid-Season: When you hill the plants a second time, you can side-dress with a bit more fertilizer or some compost.
Pest and Disease Watch
Keep a eye out for common issues. Colorado potato beetles can be picked off by hand. Aphids can be sprayed off with water.
The biggest disease threat in our humid zone is often blight. Ensure good air circulation, water at the soil level, and rotate your potato crop to a different part of the garden each year. Don’t plant them where tomatoes, peppers, or eggplants grew the previous season, as they are related and share diseases.
Harvesting Your Zone 8b Potatoes
For “New” Potatoes
You can start stealing a few tender, small “new” potatoes about 2-3 weeks after the plants stop flowering. Just gently feel around in the hill with your hand and remove a few, being careful not to disturb the main plant to much.
For Mature, Storage Potatoes
Wait until the plant’s foliage turns yellow and begins to die back. This is the sign that the tubers have reached full maturity. Stop watering at this point to help the skins toughen up.
- Choose a dry day to harvest.
- Use a digging fork, inserting it well away from the base of the plant to avoid spearing your potatoes.
- Gently lift the plant and sift through the soil with your hands to find all the tubers.
Curing and Storage
Don’t wash potatoes right after digging. Just brush off the big clumps of soil. Let them cure in a dark, well-ventilated, and cool place (about 60-65°F) for 1-2 weeks. This allows the skins to fully set for long-term storage.
After curing, store them in a completely dark, cool (38-40°F), and humid place. A basement or root cellar is ideal. Check them periodically and remove any that start to soften or sprout.
FAQ: Planting Potatoes in Zone 8b
Can I plant potatoes in the fall in zone 8b?
Yes! Fall planting is a great option. Plant your second crop about 110-120 days before your first expected fall frost, which is usually around late August. This gives the tubers time to develop in the cooler autumn weather.
What if I missed the spring planting window?
If it’s already late spring or early summer, it’s better to wait for the fall planting window. Potatoes planted in hot soil often struggle and are more susceptible to disease. You’re better off being patient.
How deep should I plant potato pieces?
Plant them about 4-6 inches deep. The key is to remember you’ll be hilling soil around them later, so starting in a shallow trench is the most common method used by gardeners.
Can I grow potatoes in containers in zone 8b?
Absolutely. Use a large container (like a 15-gallon grow bag) with excellent drainage. The process is the same: plant, and add soil as the stems grow to hill them. Container potatoes may need water more frequently, especially during hot spells.
Why are my potato leaves turning yellow?
If it’s near the end of the season, this is normal maturation. If it’s early in the season, it could be a sign of overwatering, a nutrient deficiency, or the start of a disease like early blight. Check your watering habits and look for other symptoms like spots on the leaves.
Getting your planting time right in zone 8b sets the stage for everything that follows. By following this calender and giving your plants consistent care, you’ll be rewarded with a plentiful harvest of homegrown potatoes that taste better than anything from the store. Remember, gardening is part science and part observation, so take notes on what works best in your specific garden microclimate each year.