Plot & Sprout FAQ

Plot & Sprout provides free calculators for plant spacing, raised bed soil volume, watering, seed starting dates, fertiliser dilution, and mulch coverage. Everything runs in your browser. Seed packets, product labels, and local guidance always take priority over a general estimate.

Should I use packet spacing or the calculated spacing?

Use the packet. Spacing on a seed packet reflects the mature width of that specific variety in typical conditions. The calculator tells you how many plants a bed holds at whichever spacing you enter — it does not know what you are growing.

Why does the offset layout fit more plants?

Staggering alternate rows lets each plant sit in the gap between two plants in the row behind, so rows can sit closer together while keeping the same distance between neighbouring plants. At identical spacing that fits roughly fifteen percent more plants than a square grid.

How much extra soil should I order?

Around five to ten percent above the calculated volume. Fresh mixes compact noticeably during the first season as organic matter breaks down and watering settles the bed. Ordering slightly over avoids a second delivery charge for a small top-up.

Is a watering schedule better than checking the soil?

No. A schedule is a planning aid; the soil is the evidence. Push a finger a few centimetres down — if it is dry at that depth, water, and if it is damp, wait. Weather, soil type, mulch, container size, and plant stage all change the requirement from week to week, and local water restrictions take precedence.

How reliable is a last frost date?

It is a historical average, which means roughly half of years see frost after it. Elevation, proximity to water, and urban warmth shift it noticeably within a single region, so use the nearest local source you can find and keep fleece or cloches ready for a late cold snap after transplanting.

What happens if I start seeds too early?

Seedlings held indoors too long become leggy and root-bound while they wait for safe conditions outside, and they transplant poorly. Starting a week late is much easier to recover from than starting three weeks early.

Can I mix fertiliser stronger for faster growth?

No. Exceeding the label rate risks root burn, salt build-up in the soil, and runoff into waterways. The dilution calculator converts the label ratio into an amount for your watering can — it does not authorise a stronger mix. Follow the product label, wear the protection it specifies, and store concentrates away from children and pets.

How deep should mulch be, and does more help?

Five to eight centimetres suppresses most weeds and slows evaporation. Thinner layers break down quickly and let light through; much deeper layers can keep soil waterlogged. Always pull mulch back from stems and trunks, since piling it against bark traps moisture and invites rot.