Choose a space you can care for
Begin with the area you can realistically reach, water, and maintain. Observe the location before planning: where sunlight falls, where water collects, and how you will get to each side. A diagram cannot evaluate these conditions for you.
University of Maryland Extension’s starting guide provides broader site and preparation guidance. Use your local Extension service for region-specific timing and growing advice.
Measure the usable bed
Write down inside length and width. Exclude paths and framing. A rectangular footprint gives you a simple starting point, but make sure the centre is reachable without stepping on the growing area. The calculator accepts wide beds; that does not make every width convenient.
You can use feet, inches, metres, or centimetres. Measure both sides in the same system to avoid a conversion error.
Pick a few crops you will use
Start with a small selection rather than trying to fill every possible position. Check variety, mature size, support requirements, and locally suitable planting time. Our 18-crop spacing reference helps with spacing; it does not select crops for your climate or create a planting calendar.
Record desired quantities as final plants. Seeds sown, germination, losses, and harvest volume are separate decisions.
Make and question the layout
Enter your dimensions and crops in the bed planner. Review every spacing assumption. A supported tomato preset requires support; choosing a trellis edge does not build one or account for its shade.
If requested plants do not fit, consider fewer plants or a different bed. Do not reduce spacing merely to remove the warning. Use the spacing guide to understand the methods before changing them.
Prepare soil, then take the plan outside
Decide whether you are filling a new bed or topping up an existing one. Follow the filling guide and use the soil calculator for quantity. Material quality and nutrients require different information.
Print the plan, check its measurements against the real bed, and mark plant centres. Keep access, watering, and support practical. The plan is a starting arrangement; adjust it when conditions and plant growth show that you need more room.