Seed Starting Rack Planner
Plan each rack shelf as a distinct resource so one crowded shelf cannot hide behind unused capacity elsewhere. Different lighting or heat conditions can make those spaces non-interchangeable.
Try your own numbers
4 nominal 10 × 20 trays in a uniform orientation
Check the whole seasonGive shelves meaningful names
Names like “upper warm shelf” or “unheated lower lights” tell you where the actual plants belong. Add heat mats as separate resources. For a germination stage that requires both a mat and a lit shelf, set the second simultaneous resource in the batch editor.
Separate footprint from vertical clearance
Tray footprint describes horizontal space. Taller pots and plants may need more distance below lights, but this tool does not infer height changes. If a shelf is unsuitable for a later stage, assign that stage to a different shelf explicitly.
Check the bottleneck, not the average
An average usage of two trays can hide a week that needs six. Look at the busiest day on each shelf. Extra room is calculated for your current schedule; moving a batch or changing an explicitly flexible stage may eliminate the need to buy another rack.
Worked example
Two shelves holding two trays each are not automatically equivalent to a single four-tray resource. Keeping them separate makes stage assignments and the actual crowded shelf visible.
These calculations describe space and time, not guaranteed plant performance. Use your actual equipment and crop-specific growing guidance.