The Well Kept Garden

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Where our figures come from

Every number on this site is your own measurement run through our arithmetic, a figure a maker or supplier publishes for its own product, or a figure from an extension service, a government agency, a standards body or a trade association. This page lists every publisher we take figures from. The date beside each is when we last updated our figures from that publisher’s page.

Your measurements and our arithmetic

The calculators start from the dimensions you enter. Unit conversions use the definitions in NIST Handbook 44: 12 inches to a foot, 3 feet to a yard, exactly 0.3048 meters to a foot and 2,000 pounds to a US ton. The formulas behind each result are set out on the calculation methods page.

Public bodies and standards

University extension services, government agencies, standards bodies and the Square Foot Gardening Foundation for its own soil recipe. Depths, widths, safety limits and unit definitions come from these.

Raised bed makers

Each bed’s sizes, heights, materials and stated soil capacity come from its maker’s own product page, specification sheet or assembly guide.

Watering kit makers

Parts lists, tubing lengths, pressure figures and stated bed coverage come from each kit maker’s product page and installation manual.

Materials, suppliers and trade associations

Example weights per cubic yard, bag yields, pallet sizes, minimum loads and allowances come from the supplier or maker named beside them, and apply to its products. Lumber sizes and fastener guidance come from the wood trade associations.

How we keep these current

A bed’s published sizes are due for a fresh check 30 days after the date shown, and the planner stops offering that bed as a starting size once 60 days pass without one. Watering-kit instructions are due for review 14 days after the date shown: from then the fit checker marks its answer as incomplete, and after 30 days it gives no fit answer until the instructions are checked again.

When a maker changes a figure, we update it here and on the page that uses it. If a figure can no longer be confirmed, we take it down rather than keep an old number.

What we owe these publishers

NIST Handbook 44 is a US government publication, free to reuse. Extension and agency pages are cited by name and link. Product photographs are shown from Amazon under the Amazon Associates program and belong to their owners; they are not stored on this site.