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Short answer: Pick the sunniest spot you can reach with a hose. Choose a bed no wider than 4 ft, 24 inches deep if you want to grow most things. Lay cardboard over the grass, fill with 60% topsoil, 30% compost, 10% aeration material, and plant six easy crops rather than twenty ambitious ones. Water deeply two or three times a week rather than a little every day. That's the whole thing.
Raised bed gardening is genuinely easier than growing in the ground — you control the soil instead of inheriting it, there's less weeding, and you're not waiting for heavy spring soil to dry out before you can work.
What follows is the whole sequence, in order, with the decisions that matter flagged and the ones that don't left alone.
Step 1: Choose the spot
This decision outweighs every other one on this page, and it's the only one you can't change later. A filled 8 × 4 ft bed weighs well over a ton.
Sun. Six hours of direct sun minimum; eight is better. Fruiting crops — tomatoes, peppers, squash, beans — need the upper end. Leafy greens and herbs manage on less.
Watch the spot across an actual day before committing. Check at 9 a.m., noon and 4 p.m. and note where shade falls. Bear in mind that if you're planning in March, deciduous trees are bare and will be full by July.
Water. Can you reach it with a hose? This sounds trivial and isn't. Dragging 50 feet of hose across a lawn is how consistent watering quietly stops happening in August.
Level ground. Beds must sit level or water runs to one end. Cut into the high side of a slope rather than building up the low side.
Proximity. Closer to the door means more used. Herbs and salad at the far end of the garden get harvested in May and forgotten by August.
Step 2: Choose size and height
Width: 4 ft maximum if you can walk around both sides, 2 to 2.5 ft if it's against a fence or wall. The rule is arm's reach — you should never need to step into the bed, since compacting the soil is exactly what a raised bed exists to prevent.
Length: whatever fits. There's no ergonomic penalty for a longer bed.
Height:
- 12 inches — salad greens, herbs, radishes, bush beans. Cheapest to fill.
- 24 inches — grows essentially everything, including tomatoes, carrots and potatoes. The right default for a first bed.
- 36 inches — waist height, so you garden standing up. Buy it for your back, not for your plants.
If you're unsure, 24 inches. It removes root depth from the list of things you have to think about.
Full guide to choosing a height →
How many? Start with one or two. A single 8 × 4 ft bed is 32 sq ft, which is more growing area than it looks like and plenty for a first season. Extending later is easy; discovering you've overcommitted is not.
Step 3: Prepare the ground
You do not need to remove the grass.
- Mow it short where the bed will sit.
- Lay plain cardboard over the whole footprint, overlapping the seams by several inches. Remove tape and labels. The cardboard smothers the grass, then breaks down within a season and lets roots through.
- Loosen compacted soil underneath if the ground is hard-packed. A garden fork pushed in and rocked is enough — no need to dig it over.
- Add hardware cloth beneath the cardboard if you have gophers or voles. Skip it otherwise.
Do not lay down solid plastic or landscape fabric. A raised bed with an open bottom lets roots reach into the ground below and lets water drain away. Sealing the bottom throws away both.
Step 4: Assemble and position
Metal beds bolt together and take under an hour. Assemble in place if you can — an assembled bed is awkward to carry, and a filled one is immovable.
Check level with a spirit level before filling, not after. Leave a few inches between the bed and any fence so you can reach behind it.
Step 5: Fill it
A reliable mix:
| Component | Share | What it does |
|---|---|---|
| Topsoil or bulk garden soil | 60% | Body, minerals, water retention |
| Compost | 30% | Nutrition, soil biology, structure |
| Perlite, coarse sand or pine bark fines | 10% | Drainage and air |
Three things to know:
Don't fill a whole bed with potting mix. It's designed for containers, costs a fortune at this volume, and dries out constantly.
Buy bulk past one cubic yard. An 8 × 4 ft bed at 24 inches needs 64 cubic feet — over 40 bags. Delivered bulk soil is usually less than half the price.
In a bed 24 inches or deeper, fill the bottom third with logs, branches and leaves instead of purchased soil. Plants use the top 12 to 18 inches, and this cuts the soil bill by a third or more.
Exact soil volumes for every bed size →
How to fill a deep bed for less →
Step 6: What to plant in year one
The commonest beginner mistake is variety. Twenty crops in one bed means twenty different sets of requirements, none of which you learn properly.
Pick six. Here are the ones that reward beginners:
| Crop | Why it's forgiving | Sun |
|---|---|---|
| Lettuce and salad mix | Fast, cut-and-come-again, tolerates part shade | 4–6 hrs |
| Radishes | Ready in under a month. Good for impatience. | 6 hrs |
| Bush beans | No trellis needed, heavy yield, fixes its own nitrogen | 6–8 hrs |
| Zucchini | Almost impossible to fail. One plant is plenty. | 6–8 hrs |
| Cherry tomatoes | Far more forgiving than large-fruited varieties | 8 hrs |
| Basil, parsley, chives | Constant harvest, and you'll actually use them | 6 hrs |
| Kale or chard | Productive for months, tolerates cold and heat | 6 hrs |
Leave for year two: cauliflower, celery, melons, corn (needs a block to pollinate), and full-length carrots, which want settled soil rather than a freshly filled bed.
Placement within the bed: tall crops on the north side so they don't shade shorter ones. Trellised beans and staked tomatoes at the back; lettuce and radishes at the front.
Spacing: follow the seed packet, and resist crowding. Two healthy plants outproduce five struggling ones, every time.
Step 7: Watering
More first-year gardens fail on water than on anything else — usually from watering little and often rather than too little overall.
Water deeply and less frequently. Two or three good soakings a week beats a daily sprinkle. Shallow watering keeps roots near the surface where they dry out fastest; deep watering pulls them down where the soil stays moist.
Check before watering. Push a finger two inches into the soil. Damp means wait.
Water in the morning. Plants enter the heat of the day hydrated, and foliage dries before evening, which reduces disease.
Mulch the surface. Two inches of straw or shredded leaves cuts evaporation dramatically and suppresses weeds. This single step is the highest-return thing you can do after filling the bed.
Raised beds do dry faster than open ground — better drainage is the point, and this is its cost.
First-season mistakes worth avoiding
Planting too early. Air temperature lies. Soil temperature governs germination, and cold soil means seeds sit and rot instead of sprouting. Wait until night temperatures are reliably above 50°F for warm-season crops.
Too many crops. Covered above, and worth repeating.
Skipping mulch. It looks optional and isn't.
Fertilising a new bed heavily. Fresh compost-rich soil has plenty for the first season. Excess nitrogen gives you enormous leafy tomato plants with no fruit.
Not expecting settling. Soil drops an inch or two in year one, more if you layered the bottom. Top up with compost each spring — this is normal, not a fault.
Giving up in August. Midsummer is when everything looks tired and weedy. Push through — autumn crops of lettuce, spinach and radish sown in late summer are among the easiest of the year.
A first-year timeline
| When | What to do |
|---|---|
| Late winter | Choose the spot, order the bed, order soil. Watch where sun falls. |
| Early spring | Lay cardboard, assemble, fill. Sow cool-season crops: lettuce, radish, peas, spinach. |
| After last frost | Plant warm-season crops: tomatoes, beans, zucchini, basil. Mulch. |
| Summer | Water deeply, harvest often. Cutting greens regularly keeps them producing. |
| Late summer | Sow a second round of lettuce, spinach and radish for autumn. |
| Autumn | Clear spent plants. Add compost. Cover with leaves or mulch over winter. |
Frequently asked questions
Do I need to remove the grass before putting in a raised bed?
No. Mow it short and lay plain cardboard over the footprint. The cardboard smothers the grass and breaks down within a season, letting roots pass through into the soil below.
How deep does a raised bed need to be for a beginner?
24 inches covers essentially every common vegetable, including tomatoes, carrots and potatoes. 12 inches works for greens and herbs but limits your options.
What should I fill a raised garden bed with?
Roughly 60% topsoil or bulk garden soil, 30% compost, and 10% aeration material such as perlite or coarse sand. Don't fill an entire bed with potting mix — it's designed for containers and is far too expensive at this volume.
How often should I water a raised bed?
Deeply two or three times a week rather than lightly every day. Check by pushing a finger two inches into the soil; if it's damp, wait. Morning is the best time, and mulching the surface cuts water needs substantially.
What are the easiest vegetables to grow in a raised bed?
Lettuce, radishes, bush beans, zucchini, cherry tomatoes, kale or chard, and soft herbs like basil and parsley. Pick around six rather than trying twenty.
Can I put a raised bed on concrete or a patio?
Yes, but the bed height becomes your entire root zone since roots can't reach into the ground below. Choose 24 inches or more, and make sure water can drain away rather than pooling underneath.
How many raised beds do I need?
Start with one or two. A single 8 × 4 ft bed gives 32 sq ft of growing area, which is plenty for a first season. Extend once you know what you actually grow and eat.
When should I plant in a new raised bed?
Cool-season crops such as lettuce, peas, spinach and radish can go in as soon as the soil is workable. Wait for night temperatures to stay reliably above 50°F before planting tomatoes, beans, peppers and squash.
Keep reading
- Choosing between 12", 24" and 36" beds — root depth by crop, cost, and who each height is for
- How much soil you'll need — exact volumes for every bed size and shape
- Filling a deep bed for less — cut the soil bill by up to half
- Garden layout and spacing — bed widths, path widths, and worked plans
- Metal beds in hot climates — what actually happens, and what to do about it