Vegetable Gardening Glossary

A plant that completes its whole life — seed, growth, flower, seed again — in one season, then dies. Almost everything in a vegetable garden is an annual, which is why you sow again each year.

Why it matters: It means an empty bed in autumn is normal, not a failure.

When a leafy or root crop suddenly shoots up a flower stalk and stops making the part you wanted to eat. Heat and lengthening days trigger it. Lettuce and spinach turn bitter once it happens.

Why it matters: It is the single most common reason a spring crop of greens 'goes wrong' in June.

A crop that grows best in spring and autumn temperatures and tolerates some frost — peas, spinach, lettuce, radishes, kale, carrots, onions.

Why it matters: These go in weeks before your last frost, and they are what you plant again in late summer for autumn.

The first one or two rounded leaves a seedling puts out. They came packed inside the seed and rarely look like the adult plant. The next pair are the 'true leaves'.

Why it matters: Thinning and potting-on advice is usually keyed to true leaves, not these.

A fungal problem that makes healthy-looking seedlings collapse at the soil line overnight. Caused by soil that stays too wet with too little air movement.

Why it matters: It is the main way indoor seed-starting fails, and it is prevented rather than cured.

The rough number of days from sowing until you can pick. For tomatoes and peppers it is counted from the day you transplant, not from seed — the seed packet will say which.

Why it matters: It is how you work out whether a crop can finish before your first autumn frost.

Tomato growth habits. Determinate varieties grow to a set size and ripen most of their fruit at once. Indeterminate ones keep growing and keep fruiting until frost.

Why it matters: Determinate suits containers and batch cooking; indeterminate suits a steady supply but needs real support.

Planting seed straight into the ground or container where it will grow, instead of starting it indoors and moving it.

Why it matters: Fast crops and root crops nearly always do better this way — carrots especially resent being moved.

The average dates of the last freezing night in spring and the first in autumn. Every planting date in gardening is expressed relative to them.

Why it matters: An 'average' date is where the chance of frost drops below 50 percent, so it is a coin flip, not a guarantee. Waiting a week past it is the safer read for tender crops.

How much cold a crop survives. Hardy crops go out as soon as the soil can be worked; half-hardy about 2 to 3 weeks before the last frost; tender crops only after it; very tender 2 to 3 weeks after.

Why it matters: Getting this wrong is how a whole tray of seedlings dies in one night.

The moment a seed wakes up and sprouts. It depends far more on soil temperature and steady moisture than on the calendar.

Why it matters: Cold soil is why seed 'never came up' — beans rot below 60°F, cucumbers and squash want 70°F.

Gradually introducing indoor-raised seedlings to outdoor sun, wind and cold over 7 to 10 days before planting them out.

Why it matters: Skip it and indoor leaves scorch or wilt beyond recovery within a day or two. It is not optional.

A number from 3 to 10 describing your average coldest winter temperature. It is a winter-survival rating for perennials.

Why it matters: It is not a frost-date band, even though nearly every gardening site treats it as one. Use it as a first guess, then get your real frost dates from a weather station near you.

A 2-inch layer of straw, shredded leaves or bark spread over the soil surface around plants, kept an inch clear of the stems.

Why it matters: It holds moisture, suppresses most weeds and steadies soil temperature. The highest-value half hour in the whole garden.

A plant that lives for several years, dying back and returning each season. Asparagus, rhubarb and most herbs are perennial.

Why it matters: Perennials need a permanent spot, so plan them at the edge of a bed where you will not dig them up.

How acidic or alkaline your soil is, on a scale where 7 is neutral. Most vegetables want 6.0 to 7.0.

Why it matters: Well outside that range, plants cannot take up nutrients even when the nutrients are present — which looks like a feeding problem but is not.

Moving a seedling into a larger pot when its roots fill the one it is in, usually 3 to 4 weeks after sowing.

Why it matters: A root-bound seedling stalls, and a stalled seedling is outperformed by one sown weeks later.

Potting mix is a light, sterile blend for containers. Garden soil is what is in the ground. Compost is decomposed organic matter used to improve either.

Why it matters: Garden soil compacts into a brick in a pot and drowns roots. Potting mix in a large raised bed is expensive and drains too fast. They are not interchangeable.

A finer, faster-draining, sterile mix made specifically for germinating seed indoors.

Why it matters: It is the main defence against damping off, and unlike garden soil it carries no weed seeds or pathogens indoors.

Scattering a little fertiliser or compost along the row beside growing plants, mid-season, then watering it in.

Why it matters: It feeds hungry crops like tomatoes and squash at the point they need it, without disturbing roots.

Sowing a short row of the same crop every couple of weeks instead of the whole packet at once.

Why it matters: You get a steady supply rather than thirty radishes in one week. The easiest way to get more from a small bed.

Pulling out surplus seedlings so the ones left have their full spacing. Snip at soil level for crops that dislike root disturbance.

Why it matters: It feels wasteful and beginners skip it. Crowded plants compete for light and water and all of them underperform.

As a verb, moving a young plant into its final position. As a noun, the young plant itself — also called a seedling, start or plug.

Why it matters: 'Set out transplants after last frost' on a seed packet means this.

The leaves that appear after the rounded seed leaves and actually look like the adult plant.

Why it matters: 'Thin once seedlings have their first true leaves' is the standard cue for thinning and potting on.

A crop that needs warm soil and warm nights and dies at the first frost — tomatoes, peppers, beans, cucumbers, squash.

Why it matters: These wait until after your last frost, and rushing them into cold soil gains you nothing.