About
About SowWindow
SowWindow helps turn a few garden decisions into a plan you can use: when you intend to sow, how many plants fit, which batches to repeat, and what you want to take outside on paper. You supply the garden’s dates and assumptions. The tools make the calculations visible.
Reviewed Oct 29, 2026
Who runs this website
This website is operated under the SowWindow name. Use the Contact and help page for product questions, corrections, or privacy requests.
Five practical planning tools
The seed-starting calendar uses your frost dates and supported crop rules to show relevant planting actions. The spacing calculator places plant centers inside a rectangle or circle. The seed-quantity calculator translates a target plant count and your rates into an estimate. The succession planner builds a sequence from a start, interval, and cutoff.
You can keep calendar tasks and planting layouts in a seasonal plan, adjust tasks, add notes, and mark work complete. Other estimates remain useful on their own; record their assumptions in your task notes when they matter to a saved plan.
The fall planting calculator works backward from an autumn frost reference using the maturity days on your seed packet and an editable growth allowance. It distinguishes sowing from transplanting, so nursery time is not silently included in a transplant-to-maturity figure.
A bounded crop directory
The first crop collection covers 24 vegetables and herbs. The aim is to make each supported task explainable. A crop is not given every possible action merely to fill the calendar, and a missing timing field is not replaced with a guessed number.
Source notes explain where a reference came from and the conditions that matter. A nursery interval, a direct-sowing trigger, and a latest-sowing reference can mean different things. Follow the linked original guidance when you need the wider growing context.
Your choices stay visible
A calendar calculation cannot inspect soil, seedlings, a variety, or tomorrow’s weather. The dates are planning aids. You can change them and record why, while keeping manual choices distinct from source-based results.
The same applies to space and seed estimates. A drawing counts the points in the chosen arrangement; it does not claim optimal packing or guarantee a yield. A germination percentage is your assumption unless you have identified evidence for that particular value.
Keep your own copy
Plans are saved in the browser you use. JSON backups keep the editable structure, while PDF, CSV, ICS, and SVG serve printing, spreadsheet, calendar, and layout tasks. There is no automatic cloud synchronization or shared account workspace.
Keep a backup before changing browsers, clearing site data, or revising a plan you want to preserve. A local save error should leave your work visible and give you a way to download it rather than pretending everything is safely stored.
Learn the method
The methodology page explains the calculations, boundary rules, and source handling. Blog articles discuss planning choices; the Docs section gives practical instructions and error recovery. Start with whichever task you need today, then return to the assumptions when the garden or your plans change.