Start with soil, not seeds

Fill your raised bed with soil before you plant anything. The soil is what holds water, feeds your plants, and determines whether they live or fail. Most raised beds need a mix: roughly 40 percent topsoil, 40 percent compost, and 20 percent perlite or coarse sand to help water drain. You can buy bags of each and mix them in the bed, or buy pre-mixed raised bed soil from a garden center.

Fill the bed so the soil sits about an inch below the rim. Water it thoroughly and let it settle for a day or two. The soil will compact slightly, and you want to see how much it drops before you plant. If it drops more than an inch, add more soil.

The soil temperature matters too. Most vegetables and herbs germinate best when soil is between 60 and 70 degrees Fahrenheit. If you are planting in early spring, wait until the soil has warmed up — you can check it with a soil thermometer from any garden center. Cold soil will rot seeds before they sprout.

Key Takeaways

  • Fill your raised bed with a mix of topsoil, compost, and perlite, then water and let it settle before planting.
  • Plant seeds or seedlings at the depth and spacing listed on the seed packet or plant label, not by guessing.
  • Water gently after planting and keep the soil moist but not waterlogged for the first two weeks while roots establish.
  • Plant in rows or a grid pattern so you can see what is growing where and harvest without stepping on neighboring plants.
  • Succession plant every two to three weeks if you want continuous harvests of fast-growing crops like lettuce and beans.

Plant seeds or seedlings at the right depth

The seed packet tells you how deep to plant and how far apart. Follow it exactly. A seed planted too shallow will dry out; planted too deep, it will rot or run out of energy before it reaches sunlight. Lettuce seeds go a quarter inch down. Beans go an inch down. Tomato seedlings go deep enough that soil covers the lowest leaves.

Space plants according to the packet. Crowding saves space but kills yields — plants compete for water and nutrients, and air cannot circulate, which invites mold and disease. If the packet says 6 inches apart, measure it. A ruler or measuring tape takes 30 seconds and prevents thinning seedlings later.

Plant in straight rows or a grid. It looks neater, but more importantly, it lets you see what is where. When seedlings come up, you will know which are weeds and which are your plants. You will also know where to step and where not to step when you harvest.

Water when ready and keep soil moist for two weeks

Water gently right after planting, using a watering can or a hose on mist. You want the soil wet to the depth of the seed or root ball, not puddled on top. Puddling washes seeds away and compacts soil.

For the next two weeks, check the soil every day. It should feel moist an inch down but not soggy. Soggy soil suffocates roots and causes rot. If the top inch is dry, water. If it is still moist, wait. In hot weather you may water daily; in cool weather, every two or three days.

Once seedlings are up and growing, you can water less often but more deeply. Soak the soil so water reaches 6 inches down, then let the top inch dry out before watering again. This teaches roots to grow deeper and makes plants more drought-resistant.

Harden off seedlings before planting them outside

If you started seeds indoors or bought seedlings from a nursery, they have lived in a sheltered environment. Planting them straight into a raised bed in full sun and wind will shock them. Harden them off instead: put them outside in a shaded spot for a few hours on day one, then gradually increase sun and time over a week. By day seven, they can handle a full day outside.

Hardening off takes a week but cuts transplant shock and death rates in half. It is worth the small effort. If you cannot watch them daily, at least put them in dappled shade for two or three days before planting.

Plant cool-season and warm-season crops at the right time

Cool-season crops — lettuce, spinach, peas, broccoli, cabbage — tolerate frost and actually taste better in cool weather. Plant them in early spring (as soon as soil can be worked) and again in late summer for a fall harvest. They bolt or turn bitter in summer heat.

Warm-season crops — tomatoes, peppers, beans, squash, cucumbers — need soil at least 60 degrees and air temperatures above 50 at night. Plant them after the last frost date in your area. You can find your frost date by searching "[your city] last frost date" online, or ask at a local garden center.

Succession planting stretches your harvest. Instead of planting all your lettuce at once, plant a small section every two weeks. You will have lettuce ready to pick continuously instead of a glut followed by nothing.

Add support for tall plants before they need it

Tomatoes, peppers, pole beans, and peas need stakes, cages, or trellises. Install them when you plant, not later. Driving a stake through roots damages them. A tomato cage should go in the ground the same day as the seedling. A trellis for peas should be in place before you plant the seeds.

Tie plants loosely to stakes as they grow — use soft cloth strips or plant ties, not wire or string that cuts into stems. Check ties every week and loosen them as the stem thickens.

Mulch after plants are established

Once seedlings are 3 to 4 inches tall and growing steadily, spread 2 inches of mulch around them. Use straw, shredded leaves, or wood chips. Mulch keeps soil cool, holds moisture, and blocks weeds. Do not pile it against plant stems — leave a 2-inch gap so air can circulate and rot does not set in.

Avoid hay if you can; it contains seeds that will sprout as weeds. Straw is better. Wood chips work for perennials and shrubs but can tie up nitrogen in vegetable beds, so compost is the safest choice for vegetables.

Frequently Asked Questions

Can I plant seeds and seedlings in the same bed at the same time?

Yes. Plant seeds in one section and seedlings in another. They have different watering needs for the first two weeks — seedlings need consistent moisture but not waterlogging, while seeds need to stay moist but not soggy. Once both are established, they need the same care.

What do I do if seedlings get leggy or pale indoors before I can plant them outside?

They are not getting enough light. Move them closer to a window or under a grow light. Leggy seedlings will survive transplanting but will be weak and slow to produce. If you are starting seeds indoors next year, give them 14 to 16 hours of light per day, just a few inches above the seedlings.

How often should I fertilize after planting?

If you mixed compost into your soil, you do not need to fertilize for the first month. After that, feed every two to three weeks with a balanced fertilizer diluted to half strength. Heavy feeders like tomatoes and squash need more; leafy greens need less. Follow the label on whatever fertilizer you choose.

Can I plant in a raised bed in fall?

Yes, if you plant cool-season crops. Lettuce, spinach, kale, and root vegetables like carrots and beets grow well in fall and often taste sweeter after a frost. Plant them six to eight weeks before your first frost date so they have time to mature before hard freezes arrive.

What if nothing sprouts after two weeks?

Check the soil temperature and moisture first. If soil is cold or waterlogged, seeds rot. If it is dry, they never germinated. If conditions were right, the seeds may have been old or stored poorly. Buy fresh seeds and try again. Always check the date on the packet — seeds older than two years have lower germination rates.