How To
Knowing how to know when potatoes are ready to pick can mean the difference between tender, flavorful tubers and tough, shriveled ones. Too soon, and you’ll dig up small, underdeveloped potatoes—too late, and you risk splitting or spoilage.
The key is learning to read your plants like a pro, whether you’re growing in soil or containers.
Most gardeners wait 70-120 days after planting, but timing varies by variety. New potatoes can be ready in as little as 60 days, while maincrop types need the full season.
The good news? Your plants will give you clear signals—yellowing foliage, blooming flowers, and even the way the soil feels when you dig.
In this guide, I’ll walk you through the 3 foolproof signs that your potatoes are ready to pick, plus how to test them without damaging the crop.
Whether you’re a first-time grower or a seasoned gardener, these tips will help you harvest at the perfect moment for maximum yield and taste.
Ready to dig in? Let’s break down the visual cues and hands-on methods that’ll have you pulling up potatoes like a harvesting expert.
3 Visual and physical signs potatoes are ready to harvest
Knowing when to harvest potatoes can feel like guessing—until you spot these 3 clear signals your tubers are ready. The key lies in observing both the above-ground foliage and the underground tubers.
Early harvesting gives you small, waxy new potatoes, while waiting too long risks shriveled or split tubers that spoil quickly. Let’s break down the foolproof signs to time your harvest perfectly, whether you're growing new potatoes (harvested early) or maincrop varieties (left until fully mature).
First, focus on the plant’s foliage—this is your first clue. When 70-90% of the leaves turn yellow and start to die back, it’s a strong indicator that the tubers below have reached maturity. This process, called senescence, signals the plant is redirecting energy to the tubers.
For new potatoes, you can harvest slightly earlier when the plant is still green but flower buds appear. The key difference? New potatoes are harvested for size (usually 1-2 inches in diameter), while maincrop varieties are left until the plant fully dies back.
Next, test the tuber firmness—this is where many gardeners go wrong. Use your thumbnail to gently press the soil near the plant’s base. If you feel resistance (like pushing into a firm apple), the tubers are likely ready.
For new potatoes, aim for 2-3 inches in diameter when pressed. For maincrop varieties, wait until the tubers feel firm but slightly give when squeezed, indicating they’ve reached full size. Pro tip: Avoid pressing too hard—you don’t want to bruise the tubers before harvest.
Here’s where it gets exciting: the stem test. When you carefully dig up a small sample, check the stem end of the tuber. If it’s yellow and dry, the potato is ready. If it’s still green, it’s not mature enough.
This is especially critical for maincrop varieties, where waiting too long can lead to skin splitting or disease entry points. For new potatoes, the stem end may still be slightly green, but the tuber should be plump and firm to the touch.
Don’t overlook the seasonal timing—this varies by potato variety and your local climate. In cooler regions, potatoes may take 100-120 days to mature, while in warmer climates, they might be ready in 70-90 days.
For example, Yukon Golds (a maincrop) are best left until the plant fully dies back, while Red Pontiacs (a new potato variety) can be harvested as soon as they reach 1-2 inches in size.
Always check the seed packet for variety-specific guidelines, as some potatoes are bred for early harvest while others prioritize storage life.
One common mistake is relying solely on days since planting. While most potatoes need 70-120 days, weather conditions play a huge role. A cool, wet summer can delay maturity, while a hot, dry spell might speed it up.
That’s why combining visual cues (like foliage color) with physical tests (like tuber firmness) gives you the most accurate harvest timing. For container-grown potatoes, the same rules apply, but check tubers every 2 weeks starting at 50 days—they often mature faster due to limited root space.
If you’re unsure, dig a small test sample—this is the safest way to check without committing to a full harvest. Use a hand fork or trowel to gently loosen the soil near the plant’s base, then brush away the dirt to inspect the tubers.
Look for uniform size and color: ready potatoes should have a smooth, firm skin with no green spots (a sign of solanine, a toxin that develops from exposure to light). If the tubers are small and still green, wait another 1-2 weeks and test again.
For maincrop varieties, timing is critical to avoid skin splitting or disease. Harvest when the plant is completely dead (all foliage yellowed and wilted) and the tubers are large and firm.
If you’re storing them for winter, cure them first: place harvested potatoes in a dark, humid space (like a basement) for 1-2 weeks to toughen their skins. This step is especially important for long-storage varieties like Russets or Kennebecs, which can last 4-6 months in ideal conditions.
Remember, new potatoes are all about size and tenderness. Harvest them when they’re 1-2 inches in diameter, even if the plant is still green. This gives you buttery, flavorful tubers perfect for roasting or boiling.
For maincrop potatoes, patience pays off—wait until the plant is completely dead and the tubers are 3-4 inches in diameter for the best storage potential. Whether you’re harvesting early or late, always handle tubers gently to avoid bruising, which leads to rotting and spoilage.
Pro tip: Mark your planting date and set a reminder for 70-120 days later to start checking for harvest signs. If you’re growing multiple varieties, label your rows and keep a small harvest journal to track which potatoes mature fastest in your climate.
With these 3 foolproof signs, you’ll never guess wrong again—just dig, test, and enjoy your homegrown spuds at their peak! 🥔
Best harvesting methods for different potato types (new vs. maincrop)
Not all potatoes play by the same rules—new potatoes and maincrop varieties demand different harvesting approaches. New potatoes, like Yukon Gold or Red Pontiac, mature faster (60-90 days) and need gentle handling, while maincrop types (e.g., Russet or Kennebec) take 100-120 days and require curing for storage.
Let’s break down the tools, timing, and techniques for each.
For new potatoes, the goal is speed and precision. Use a hand fork or small trowel to loosen soil around the base of the plant, then gently lift tubers from the top 6 inches of soil.
Avoid digging too deep—you’ll damage smaller, still-growing tubers. Harvest in the morning when soil is moist but not soggy to prevent bruising.
Maincrop potatoes, however, need a full-depth harvest using a sturdy digging fork or even a small shovel. Work in dry conditions (after 2-3 days without rain) to minimize soil clinging.
Cut the foliage 1-2 inches above the soil first—this signals the tubers to stop growing and harden their skins for storage.