How many plants fit in a 4 × 8 raised bed

The short answer, crop by crop

The table counts final plants for one crop on its own in a bed measured 8 × 4 ft (96 × 48 in) on the inside. It uses the same rules as the plant spacing calculator: plants sit on a grid at the stated spacing, and every plant keeps half a spacing between its centre and the frame.

Spacing presets come from the university Extension sources listed in the spacing reference. Your seed packet may give different figures for your variety; use those if they differ.

Why these numbers are lower than some charts

Many square-foot charts divide the bed into 32 squares and multiply. That works for lettuce at 12 in: 32 plants either way. It stops working for anything that does not divide neatly into 12 in, because a plant cannot straddle the frame.

Peppers at 18 in are a good example. 96 in holds 5 plants along the length and 48 in holds 2 across, so the bed takes 10. A chart that allows “one pepper per 2.25 ft²” would suggest about 14, but the leftover strips are too narrow for another whole plant.

Large crops show it most clearly. Summer squash at 48 in fits 2 plants in an 8 × 4 ft bed, one at each end, with every plant still 24 in from the frame.

Measure inside the frame

A bed sold or built as “8 × 4 ft” is often that size on the outside. With 1.5 in boards the soil inside is 93 × 45 in, which changes more than you might expect:

• Head lettuce at 12 in drops from 32 to 21, because 45 in holds 3 rows instead of 4.
• Supported tomatoes at 24 in drop from 8 to 3, and eggplant from 8 to 3: 45 in is too narrow for a second row at 24 in with 12 in at each edge.
• Summer squash at 48 in drops from 2 to 0: the inside width is less than one plant’s spacing.

Measure the soil surface from the inside of one board to the inside of the opposite board. The first-garden guide has a drawing of where to measure.

Blocks or traditional rows

The last column uses traditional row spacing: plants closer together within a row, with a wider gap between rows for walking and hoeing. In a 4 ft bed that you reach into from the sides, that walking gap is mostly lost space.

Head lettuce shows the difference: 32 plants in blocks against 8 in rows, because rows 30 in apart leave room for only 1 row across 48 in. In this table every crop except summer squash fits fewer plants in rows than in blocks; the squash row preset puts plants 24 in apart along the row, closer than its 48 in block spacing. Row counts for radish, pea and other thickly sown crops assume you sow along a line and thin to the stated distance.

The spacing methods guide explains both systems in more detail.

Mixed beds: what actually fits

Most beds hold several crops. The planner gives each crop its own strip across the full 8 ft length, in list order, so the counts above cannot simply be added up. Here is a typical summer request: 2 tomato (supported), 4 pepper, 16 bush bean, 6 head lettuce.

Every plant fits if the bed is 60 in wide inside, or you can move the lettuce up the list, in which case a crop further down loses space instead. The planner reports these options with your own numbers.

Open this plan in the bed planner

A large crop changes the whole bed. With 2 summer squash at 48 in, the squash strip takes the full 48 in width, so 16 bush bean, 32 radish have no room left: 2 of 50 placed.

Open this plan in the bed planner

Plan your own 4 × 8 bed

1. Measure the inside length and width.
2. List your crops with the most important first.
3. Enter the number of final plants you want, not seeds.
4. Check the result for unmet plants and, if there are some, the width or length the planner says would fit them.

Open the bed planner