Potatoes

Potatoes are one of the few common garden vegetables genuinely grown from a piece of themselves rather than true seed - a whole or cut seed potato with at least one healthy eye, planted directly into the ground - and the entire harvestable crop grows underground on modified stems called stolons, not on roots, which is why the plant's above-ground care and its below-ground yield are more loosely connected than most first-time gardeners expect going in.

Chitting Before Planting

Chitting - setting seed potatoes in a cool, bright spot for two to four weeks before planting so they sprout short, sturdy green shoots - isn't strictly required, but it reliably shaves one to two weeks off the time to emergence and gives the plant a head start on the growing season, which matters more in shorter-season zones than in long ones. A dark storage spot produces long, pale, fragile sprouts that snap off easily during planting; a bright spot produces the short, tough ones you actually want.

Hilling: Why It's Not Optional

Potato tubers that get exposed to light turn green and develop solanine, a bitter compound that's mildly toxic in quantity - which is why hilling (mounding soil or mulch up around the base of the growing plant every few weeks) isn't a cosmetic step but a genuine yield-and-safety requirement, keeping developing tubers covered as the plant grows taller. Skipping hilling doesn't just risk green tubers; it also caps how many tubers the plant can set, since new tubers form in the buried stem section that hilling creates.

Companions: Beans, Horseradish, and Marigold

Bush beans contribute real nitrogen through root-nodule fixation, useful to a crop that draws fairly heavily on soil nutrients over a long season. Horseradish is a traditional potato-patch companion on the reasoning that its strong-scented roots and leaves help mask the potato plant's own scent from Colorado potato beetles, a widely repeated claim we haven't found isolated in a controlled trial - worth trying since horseradish is a low-maintenance perennial anyway, but not something to count on as pest control. Marigold offers the same documented root-knot-nematode suppression here as it does for tomatoes and peppers, genuinely useful in soil with known nematode pressure.

The Blight Risk With Tomatoes

Blight is the reason tomatoes top this list: both crops are nightshades susceptible to the identical early and late blight fungi, so a potato bed planted too close to tomatoes gives a single infection two hosts to spread through instead of one, and this is the single most important antagonist relationship a potato grower needs to plan around. Fennel's allelopathic root exudates suppress potato growth the same way they suppress most neighboring plants. Cucumbers share a more moderate shared-disease-risk profile with potatoes (several fungal pathogens cross both), and sunflower and winter squash are both listed as traditional-lore antagonists on thinner nutrient-competition and allelopathy reasoning we can't point to strong direct evidence for.

Curing and Storage

Freshly dug potatoes intended for storage (rather than immediate eating) benefit from curing - resting in a cool, humid, dark spot for one to two weeks before storage - which toughens the skin and heals small harvest nicks, substantially extending how long they'll keep afterward. Potatoes eaten fresh within a few days of digging skip this step without any loss.

Determinate vs. Indeterminate Potato Varieties

Early-maturing (determinate) potato varieties set most of their tubers in one layer close to the seed piece and stop hilling benefit fairly quickly, while later-maturing (indeterminate) varieties keep setting new tubers higher up the buried stem as the season goes on and reward continued hilling well into midsummer. Knowing which type you're growing changes how long it's worth continuing to mound soil - hilling a spent early variety in August accomplishes nothing, while stopping too soon on a late main-crop variety leaves real yield sitting unformed in the buried stem.