Build a garden budget you can phase without paying twice

Decide what must work before what must look finished

List the essential outcomes: safe usable access, a workable water and drainage arrangement, places for household activities and plants that fit the site. Next list desirable improvements. Keep decorative upgrades separate so they cannot quietly consume the money reserved for essential work.

Inspect what can be retained, repaired, moved or reused. The RHS budget guide encourages working with existing features and materials where appropriate. Reuse still has labour, transport and suitability costs. Reject reclaimed material that cannot be assessed for its intended use; “free” is not a technical specification.

Measure the quantities before inserting prices

Start with the drawing and quantity calculator. Distinguish a geometric bed volume, a supplier’s bag size and a final order allowance. Count actual plant positions, then decide whether the purchase is plants, plugs or seed packets. Forty-one crop positions do not mean forty-one seed packets.

Keep a quantity note next to each line: source of measurement, unit, specification and allowance. A quote for “soil” is not comparable with another until the material and delivered volume are clear. Never turn volume into weight without the actual material’s bulk density and appropriate loading checks.

Check the complete worked estimate

This independent illustrative price example uses user-entered currency units; it is not a market-price claim or a quotation. Ten plants at 5 cost 50; 2 yd³ of material at 48 cost 96; 30 ft of edging at 3 cost 90; delivery is 75. Subtotal: 311. With no tax and a 10% contingency on that subtotal, the total is 342.10.

The default budget calculator reproduces those values and allows you to replace every line. Currency changes the label, not the exchange value. Its tax calculation applies the entered percentage to the whole subtotal, and contingency applies to subtotal plus tax. If local tax treatment differs by item, split the estimate into appropriate separate calculations or obtain a supplier’s itemized tax quotation.

This price example is deliberately separate from the 600-litre mulch example. Two cubic yards is a different volume; combining them would create a false quantity-to-price correspondence.

Include the work behind the finished photograph

Add professional assessment where needed, permissions, site access, preparation, excavation, disposal, base materials, edging, delivery, labour, tools, temporary protection, tax and recurring care. Ask suppliers which items a quote excludes. Record whether the price is provisional, fixed, or waiting on a site condition.

Set contingency according to uncertainty rather than treating 10% as a universal correct amount. Keep a separate unpriced-items list. A total that excludes a known but unpriced drainage issue is incomplete even when its arithmetic is exact. The calculator rejects blank prices so that an imported plant list cannot silently masquerade as a finished estimate.

Phase a small courtyard coherently

For the 6 × 4 m courtyard, phase one is observation, measurement, root/service checks and the household brief. Phase two resolves any necessary professional work, permanent access and the practical seating arrangement. Phase three establishes the 9 m² of planting with its 13 compatible positions and care plan. Phase four reviews performance before adding discretionary decoration.

Keep a functioning route and safe access between phases. Do not plant across the future delivery or excavation route, and do not buy plants months before their space is ready. If phase two reveals a problem, retain the planting budget while the design is revised.

Where the whole planting purchase cannot fit the budget, establish a clearly bounded portion and keep the remainder appropriately managed. Do not spread half the mature plant count evenly across the complete scheme and assume it will produce the same first-year result.

Review costs against the decisions

Download the itemized CSV with assumptions, record actual spending separately and compare each variance to its cause. Did quantities change, a quote exclude work, or the specification improve? That distinction helps you revise later phases without repeating the error.

Preserve both the chosen and rejected options in the brief. If maintenance cost or effort exceeds what you can sustain, simplify the design now. A smaller coherent project with an honest remaining phase is more usable than a nominally complete garden whose essential tasks were omitted.