Garden by the Numbers
Backyard vegetable garden with cedar raised beds of tomatoes, kale and lettuce at sunset
Raised beds & indoor growing

Grow more food by getting the numbers right

How much soil a bed really takes, how much light tomatoes need indoors, which heat mat fits your tray. We do the math, so you can buy the right size the first time.

Try the free calculators Plan a raised bed
32 cu ftof soil fills a 4 × 8 bed, 12 inches deep
350–520PPFD for indoor tomatoes over a 16-hour day
20 galputs one inch of water on a 4 × 8 bed
6–8 weeksfrom sowing tomatoes to your last frost date

Start with your project

Four topics, each built around the decisions that matter.

Row of wooden and galvanized raised garden beds planted with young vegetables

Raised Beds

Height, width, materials, soil volume and awkward sites such as slopes and balconies.

Basil, lettuce and parsley growing on a shelf under white LED grow lights

Grow Lights

Size a light by PPFD and DLI, not by the wattage printed on the box.

Green vegetable seedlings in a black cell tray on a wooden bench

Seed Starting

When to sow, how much heat to give, and how to fit it all in your home.

Drip irrigation tubing running through mulch beside lettuce in a raised bed

Watering & Season

Drip systems, timers, cold frames and row covers for raised beds.

Specific answers for real situations, from sloped yards to north-facing windows.

Dwarf tomato plants with ripening fruit inside a small grow tent under an LED panel
Grow Lights

Grow light for a 3×3 tent of tomatoes

The target PPFD, actual watts and running cost for indoor tomatoes.

Wooden elevated planter of herbs and lettuce on a city apartment balcony
Raised Beds

Elevated planter weight on a balcony

Work out the wet weight of a planter and what to ask your building.

Galvanized steel raised bed next to a cedar raised bed, both planted with vegetables
Raised Beds

Galvanized vs cedar raised beds

Lifespan, heat, safety and assembly compared, with the honest limits of the data.

Waist-high cedar planter on legs filled with lettuce and herbs on a stone patio
Raised Beds

Raised bed height for bad knees

Which height suits standing, sitting or a wheelchair, and what each one costs in soil.

Seed cell tray with sprouts sitting on a black seedling heat mat
Seed Starting

Heat mat size for a 72-cell tray

A fit chart by tray count, and why a thermostat matters.

Free calculators

Enter your own dimensions and get a usable number. Every formula is shown on the page.

Raised bed soil calculatorCubic feet, cubic yards, bag count and wet weight for any bed.Grow light cost calculatorMonthly and seasonal power cost from actual watts and your rate.DLI calculatorConvert PPFD and hours into DLI, or find the PPFD you need.Seed starting calendarSowing dates for common crops from your last frost date.Drip line calculatorTubing length, emitter count, flow rate and time per inch of water.

No fake testing

We say plainly when a guide is research rather than hands-on experience.

Sources you can check

Each guide lists the extension publications and specs behind its advice.

Fit before features

We start from your space and your crops, then narrow down what to buy.