How much garlic to plant

How this calculation works

The core relationship is simple and it is the reason garlic is easy to plan: one clove planted becomes one bulb harvested. Not two, not a handful — one. So the cloves you plant equals the bulbs you want, plus a margin for the ones that rot or come up blind.

Converting that clove count into an order is where the units bite. A pound of porcelain hardneck holds about 38 cloves because the cloves are enormous. A pound of silverskin softneck holds about 72. Both plant the same length of row at the same spacing, but one order is nearly twice the weight of the other. Order by the pound without checking cloves per pound and you will be short by half a bed.

Bed space follows from spacing. The table above recalculates every variety against your own numbers, so you can see the seed weight change while the row length stays put.

Saving your own seed costs a quarter of the harvest

"Save your own seed garlic" is standard advice and it is good advice. What is almost never said is how much of the crop it consumes, and the honest number surprises people.

Since one clove makes one bulb, replanting the same area next year means holding back enough bulbs to supply the same number of cloves. For a porcelain hardneck averaging four cloves per bulb, that is one bulb in four — 25% of the harvest goes straight back in the ground. Not the 10% people tend to budget.

Variety changes this more than anything else you can control. A silverskin softneck carrying fourteen cloves per bulb needs one bulb in fourteen, about 7%. Same bed, same work, a third of the seed reserve. If you intend to be self-sufficient in garlic, that ratio is a stronger argument for softnecks than flavour is for hardnecks.

There is a compounding trap on top. The advice to plant your biggest bulbs is correct — clove size drives next year's bulb size directly. But the biggest bulbs of a hardneck tend to carry fewer, larger cloves, so selecting for size gradually pushes your seed reserve upward as a fraction of the crop. Worth knowing before you wonder why year three needs more seed than year one.

Grow two varieties or run out in December

Storage life varies more between garlic types than almost any other stored crop, and it is the difference between garlic all year and garlic until Christmas. Rocamboles — the best-flavoured garlic there is, by wide agreement — keep about five months. Harvest in July, and you are out by December with seven months to go.

The instinct is to plant more. It does not work: the surplus bulbs go soft on exactly the same schedule as the rest, so a bigger planting of a short keeper just means throwing more away in January. Quantity cannot solve a storage-life problem.

The fix is two varieties in the same bed, planted the same day. A hardneck for flavour and for the scapes in June, eaten from July through the winter. A softneck — silverskin or artichoke — for the back half of the year, still good the following June when the new crop is nearly in. It costs nothing extra in space or labour, and it is the single change that turns garlic from a seasonal crop into a year-round one.

Where these numbers come from

Cloves per pound follow University of Maryland Extension and seed-house catalogue figures: hardnecks 35–50, softnecks 50–80, with the values here set near the middle of each horticultural group. Cloves per bulb are the same sources — porcelains 4–6, rocamboles 8–10, artichokes and silverskins 12–16.

Spacing at six inches in the row and six inches between rows is the standard commercial and home-garden figure. Four inches raises bulb count and lowers average size; eight inches does the reverse. Total yield by weight moves surprisingly little across that range, which is why the choice is really about whether you want more heads or bigger ones.

Storage months assume properly cured garlic — two to three weeks with tops on, out of sun with air moving — held at room temperature with low humidity. Uncured garlic keeps a fraction as long, and the refrigerator is actively wrong: garlic held at fridge temperature interprets it as winter and sprouts.

What this calculator can't tell you

Yield assumes a decent bed. Garlic is not a heavy feeder by the standards of, say, brassicas, but it is completely intolerant of wet feet — poorly drained soil produces small bulbs regardless of everything else you do right. If your ground stays soggy in March, raised beds change the outcome more than any variety choice.

Nor can it judge whether a variety suits your winter. Hardnecks need a genuine cold period to divide into cloves properly and tend to disappoint in the deep south; softnecks, particularly artichoke types, handle mild winters much better. If you are below about zone 8, that constraint outranks everything on this page.

One warning worth repeating because it costs whole crops: do not plant supermarket garlic. Much of it is treated to suppress sprouting, most of it is a softneck bred for a climate that is not yours, and — the real risk — it can carry white rot, a soil-borne disease that persists in the ground for twenty years and ends garlic and onion growing on that plot. Certified seed stock from a reputable grower is cheap insurance.

Where garlic fits

Garlic goes in the ground the same weeks the rest of the fall garden is being sown, but it works on a different clock — planted in October, harvested the following July. The fall planting calendar handles everything that has to finish before frost; this page handles the one crop that is meant to sit through winter.

Once cured, garlic wants the dry side of the root cellar — 50–60% humidity, alongside the onions, never in with the carrots. And if you put up sauce, the tomato canning calculator will tell you how many jars you are seasoning. Everything you work out collects on your my homestead page.