Raised Bed Garden in a Small Lawn: Size, Soil Fill and Bricks
A raised bed garden in a small lawn works best at about 120 cm wide, any length that fits, and 25 to 45 cm high, built from brick or concrete blocks and filled with a loose mix of good soil and compost rather than whatever the builder left behind. Build it in October and you can sow winter palak, mooli and dhania into it in November. Here is how to size it, how to fill it without buying a truckload of soil, and how to work out what it will cost before you call a mistri.
In brief
- Width: about 120 cm (4 ft) if you can reach from both sides; 60 to 75 cm against a wall
- Length: whatever fits; 240 cm (8 ft) is a handy size
- Height: 25 to 30 cm for most vegetables; 45 to 60 cm if bending is hard
- Soil depth: 15 cm is the minimum; 30 cm suits mooli, gajar and tomatoes
- Paths: at least 45 cm, 60 cm if a wheelbarrow must pass
- Sun: 6 hours or more in winter, and check for afternoon shade from walls
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What size should a raised bed be?
Width is the measurement that matters. Extension services commonly advise no more than 4 feet (about 120 cm), because from either side you then reach about 60 cm to the middle and never need to step on the soil. Stepping on it squashes out the air, which is half the reason for building a bed.
Against a boundary wall you can only reach from one side, so keep it to 60 to 75 cm. Length is free: one long bed is cheaper per metre than two short ones because there are fewer corners and end walls.
How high?
Three courses of brick on edge or four to five laid flat gives roughly 25 to 30 cm, enough for leafy greens, onions and herbs. For carrots, radish and tomatoes, aim for 30 cm of loose soil, which you can get by building 25 cm high and loosening the ground underneath with a spade. Taller beds of 45 to 60 cm suit anyone with back or knee trouble, but they hold much more soil and dry faster in May.
Raised bed vs planting in the ground: which is better?
| Situation | Verdict | Reason |
|---|---|---|
| Heavy clay that waterlogs | Build a bed | Raised soil drains and warms faster |
| Rubbly builder’s fill, new house | Build a bed | Faster than repairing the ground |
| Good loam, plenty of space | Maybe | Ground beds are cheaper and stay moister |
| Sandy soil in hot dry Multan or Bahawalpur | Maybe, keep it low | Tall beds dry out fast in 45°C heat |
| Rooftop | Skip brick beds | Weight: use pots or light containers unless an engineer approves |
Not sure what your ground is like? A ten minute test is in our guide to testing soil at home.
How do you make a brick raised bed?
- Mark it out with string and pegs in the sunniest strip, long side running east to west if possible so plants do not shade each other in winter’s low sun.
- Clear and loosen. Remove grass, then dig the base one spade deep and break up hard pans. Roots will go down into it.
- Lay a footing. A shallow trench with one flat course of brick or a thin bed of mortar keeps walls level. Leave a few small gaps (weep holes) in the bottom course so water can escape.
- Build the walls. Brick or block, in mortar for permanence, or dry stacked for a low bed you may move later. Old bricks from renovation work are fine.
- Let mortar set for a few days, wetting it daily, before filling.
- Fill in layers (below), soak it, and let it settle a week before sowing.
Avoid old railway sleepers and wood treated with creosote or unknown chemicals for vegetable beds. Untreated wood is fine but will rot within a few years in our monsoon.
What soil goes in a raised bed?
A raised bed acts like a very big pot, so plain garden soil alone tends to pack down. A reliable home mix by volume:
- About 50 to 60 percent good topsoil (loamy, from a nursery or your own better ground)
- About 30 to 40 percent compost, leaf mould or well rotted gobar
- About 10 percent coarse material such as rice husk, coco chips or brick grit for air
Mix it on a tarpaulin before shovelling in. Add a few handfuls of sarson khal (mustard cake) or old manure per bed if you have them.
The bottom third trick (for beds 40 cm and taller)
Fill the lowest third with twigs, chopped prunings, dry leaves and old straw, soak it, then add the soil mix on top. It saves a lot of bought soil and rots slowly into food. The bed will sink several centimetres over the first season, so keep a few bags of compost to top it up. In a shallow 25 cm bed, skip this: there is no room for it.
How much soil and how many bricks will you need?
Do the arithmetic before buying, so the mistri and the soil supplier cannot surprise you.
- Soil volume: length × width × depth in metres. A 2.4 × 1.2 m bed filled 30 cm deep needs 2.4 × 1.2 × 0.3 = about 0.86 cubic metres, roughly 85 to 90 large 10 litre buckets.
- Bricks: the perimeter of that bed is 7.2 m. A standard brick plus mortar covers about 24 cm of length, so about 30 bricks per course. Four courses laid flat (about 30 cm high) need around 120, plus spares for breakage.
- Cost: multiply by your local brick, cement, soil and labour rates. Prices change by city and month, so ask two suppliers. Concrete blocks need fewer pieces but cost more each; dry stacked recycled bricks cost least.
How do you stop termites in a raised bed?
Termites (deemak) are a real problem in the plains, especially with wood edges and dry organic fill. Brick and concrete walls give them nothing to eat. Inside the bed, keep the fill moist rather than bone dry, avoid big lumps of undecomposed wood near the surface, and turn in compost rather than raw straw. Seal any gaps where a wooden frame touches the ground, or switch to masonry. If a colony appears, dig out the affected section, let it dry, and refill. Chemical termiticides belong to professionals and should not be used under food crops.
What to plant first
For a first winter bed in Lahore, Faisalabad, Delhi or Islamabad, sow from late October to November: palak, methi, mooli, dhania, salad leaves, with a row of onions or garlic along one edge. In Karachi, the cool window is shorter, so start in November. Our first five plants for beginners keeps choices simple, and beginner kitchen garden mistakes saves you the common setbacks.
Never build brick beds on a roof or balcony without a structural engineer’s advice: a 0.86 cubic metre bed of wet soil can weigh around a tonne. Wear gloves when handling cement, which burns skin, and keep mixed mortar away from children. Lift bricks and soil bags with a straight back and share the load. Check weep holes and nearby saucers weekly in the monsoon so water does not stand and breed mosquitoes. Do not use soil from old industrial sites, dump areas or roadside dig outs for food beds.
Raised bed questions, answered
How do I make a raised bed for vegetables?
Mark a sunny strip about 120 cm wide, loosen the ground, build brick or block walls 25 to 30 cm high with small drainage gaps, and fill with a mix of topsoil and compost. Let it settle a week before sowing.
What is the best size for a raised bed?
About 120 cm wide and as long as space allows, if you can reach both sides. Against a wall, keep it 60 to 75 cm wide.
How deep should a raised bed be for vegetables?
Fifteen centimetres is a minimum for greens, but 30 cm of loose soil suits most vegetables, including carrots, radish and tomatoes.
What soil mix should I use in a raised bed?
Roughly half to two thirds good topsoil, one third compost or old manure, and a little coarse material such as husk or coco chips for air.
Is a raised bed better than planting in the ground?
It is better on clay, rubbly fill or waterlogged sites. On good loam, ground beds work just as well and cost less.
How much does a brick raised bed cost?
It depends on local brick, cement, soil and labour rates. Work out the brick count and soil volume first, then get two quotes; a 2.4 × 1.2 m bed 30 cm high needs about 120 bricks and under 1 cubic metre of mix.
Do raised beds need a bottom?
No, in a lawn or yard leave the bottom open so roots and water reach the ground. Only beds on paving or concrete need a lining and drainage holes.
Should I put plastic at the bottom of a raised bed?
Usually not. Plastic traps water and blocks roots; lay cardboard over grass instead, which rots away.
Why is my raised bed soil sinking?
Organic matter rots and the mix settles, so beds can drop several centimetres in the first season. Top up with compost each autumn.
More bed and pot guides are collected in the Kitchen Garden section.