The last centimetre in your bed — plants that fill every gap

You've planted your bed. Tomatoes in the middle, lettuce on the edge, beans in the back row, a squash vine in the corner. The bed looks tidy. But between the plants there are a few square centimetres of soil that are... well, empty.

Those gaps aren't just an aesthetic problem. They're a missed opportunity. Per bed you might have 0.2-0.3 m² of gap — about 20% of the growing area producing nothing. Across the season that's 6-8 extra heads of lettuce or 200 radishes you didn't harvest, just because the space wasn't used.

Here are four plants that fill those gaps — fast, small, and improving your main crops along the way.

The principle: fast + small + useful

A filler plant needs three properties:

1. Fast. Maximum 6-8 weeks from sowing to harvest. Otherwise it takes longer than your main crops need to fill the gap.
2. Small. Maximum height 20-25 cm, root depth max 15 cm. Otherwise it competes with the main plants.
3. Useful. Ideally it does something good — loosens the soil, attracts beneficials, supplies nitrogen.

1. Radishes — the classic

Already mentioned in the spring post; here in the gap-filler role.

Radishes need only 4 cm² per plant and harvest in 4 weeks. So: between two tomato plants planted in mid-April that won't be big until mid-June, you have exactly the window for a radish run.

Sow in the row: a seed every 3-4 cm, 1 cm deep. Harvest all after 4 weeks, before the tomatoes claim the space. A 50 cm row between two tomato plants gives you 12-15 radishes.

2. Asian greens / pak choi — the spring secret weapon

Asian greens (mizuna, tatsoi, pak choi) grow in 3-5 weeks, have shallow roots (10 cm), and the young leaves are welcome in any salad or wok.

Where: in spots that are only free for a few weeks. Pre-crop before tomatoes, intercrop between lettuces, post-crop after early potatoes.

Sow: from March to mid-April, then again from late August. In high summer they bolt too quickly, so skip then.

Cutting trick: from 10 cm height, harvest individual leaves. Plant pushes new ones. You get 3-4 mini-harvests per sowing.

3. Marigolds — beautiful and useful

Marigold isn't a food plant (well, you can eat the flowers, but that's not the main point). It's a pollinator magnet and a nematode deterrent.

Pollinators: hoverflies, wild bees, butterflies. They land on the marigold and then move to your tomatoes/beans/cucumbers. You significantly raise the pollination rate, which directly means more yield.

Nematodes: tiny worms in the soil that damage plant roots. Marigold roots release substances that drive nematodes off. Over 2-3 seasons, measurably better soil.

Sow: mid-April to mid-May, blooms from July through to frost.

Where: outer edges of the bed, where pollinators see them first. One marigold per 50 cm of bed edge is enough.

4. Cress (or salsify-young-leaf) — soil activation

OK, I'm cheating a little here — those are two plants.

Cress (garden cress, not watercress) grows to harvest in 6-10 days. Yes, one week. It's the fastest edible plant I know. You sow, you harvest, you re-sow. In high summer you can push 3-4 cress generations through a single gap.

Plus: cress roots release mild acids that activate the soil for following plants. A bed where cress has grown several times often has visibly more crumbly soil after 2 seasons.

Salsify (scorzonera, harvested young as salad leaf) is rarer and a bit more demanding, but it has taproots that loosen the soil deep — ideal after plants with shallow roots.

If you can't decide: cress. You have nothing to lose, it costs 5 cents per sowing.

Example: how I use it

My 80×120 cm bed in June:

• 3 tomatoes in the centre (60 cm spacing, each needs ~30 cm radius, so 2 m² used out of 0.96 m² bed — the overlap is the gaps)
• 4 lettuce heads at the front-right
• 6 bush beans at the back-left

The gaps between tomatoes and lettuce are about 10×30 cm each. There are 4 such gaps. Radishes go in there, sown in April, harvested late May. Before the tomatoes are big enough to claim the space.

On the outer edges: 4 marigolds — one per side. They draw the pollinators from July onwards, which helps my bean harvest.

Between the bean rows, in spring before beans are planted, a sowing of Asian greens. Harvested by 10 May, then beans go in.

Effective: the bed that the plan says holds 13 plants actually produces, across the season, those 13 main crops + ~30 radishes

• 2 Asian-greens mini-harvests + a pollinator boost from 4 marigolds. Yield gain: hard to quantify, but tangible.

What Erntezeit does for you

Currently Erntezeit calculates main crops — "you have room for 3 tomatoes, 4 lettuces, 6 beans". Gap optimisation comes with Pro in Phase 4: it detects the geometric gaps and proposes filler-plants that fit the season.

For now: plant your main crops as planned, and sow radishes, Asian greens or cress in the remaining gaps. Costs €5-10 in seed and gives you 20% more yield.

Try the bed planner — we give you the main plan, you fill the gaps.

🦔 Stachi