Lawn Renovation Planner UK

Is your lawn thin, patchy, mossy or worn out? Our free Lawn Renovation Planner helps you decide whether to repair, overseed or replace it, then works out the grass seed, turf and top dressing you need. Add your supplier prices, plan the work around UK growing conditions and take a printable shopping list into the garden. No account is needed.

How to use the Lawn Renovation Planner

• Measure your lawn. Add the dimensions of each lawn area, or enter its known area in square metres. Exclude beds, paths and patios.
• Assess the condition. Choose the problems you can see, such as thinning grass, bare patches, compaction, moss or poor drainage. The tool suggests likely causes, not a diagnosis.
• Choose your approach. Compare overseeding, patch repairs, a new lawn from seed or laying turf. You can change the suggestion to suit your project.
• Calculate materials. Enter grass seed rates from the packet, turf roll sizes, top dressing quantities and optional supplier prices.
• Make your plan. Select your UK region, review the suggested work schedule, save your project and print the plan or export the shopping list.

How much grass seed, turf or top dressing do you need?

Measure the area you are actually treating, not necessarily the whole lawn. Use the product label for sowing rates and material coverage, as these differ between brands. The examples below show how the calculator works before additional allowances and purchase pack rounding.

Overseeding a thin lawn

A lawn measuring 50 m² overseeded at 25 g/m² requires 1.25 kg of grass seed. If your supplier sells 500 g packs, you need three packs. The correct sowing rate is the one stated on your chosen seed packet.

Repairing bare patches

An 80 m² lawn with only 20% bare patches has 16 m² needing repair. At 25 g/m², that is 400 g of seed. You do not need to calculate seed for all 80 m² unless you are also overseeding the rest.

Starting a lawn from seed

For a 100 m² new lawn sown at 35 g/m², you need 3.5 kg of seed before allowances. The RHS advises protecting newly sown areas from birds with fleece or bird tape and describes an increased sowing allowance for uncovered new lawns. The planner treats this separately from overseeding and patch repair. Read the RHS guidance on sowing a lawn.

Replacing a lawn with turf

A 20 m² area with an additional 5% for cutting needs 21 m² of turf. A standard roll may cover around 1 m², but sizes vary, so check your supplier’s roll measurements before ordering. The planner calculates the number of whole rolls you need.

Calculating lawn top dressing

A 3 mm layer over 100 m² is 0.3 m³, or 300 litres. Its weight depends on the material and its moisture content. The planner will only convert between volume and weight when you supply a density or deliberately select a labelled estimate.

Should you overseed, repair or replace your lawn?

Overseeding is usually the first option when there is still reasonable grass cover but the lawn is thin or tired. The existing grass remains in place while new seedlings help thicken it.

Patch repair makes sense when wear, pet damage or bare soil is confined to a few distinct areas. You can reseed the patches or use small pieces of turf where you need a quicker repair.

A new lawn from seed may be the better option when much of the existing lawn has failed and the underlying problem has been corrected. It takes longer to establish but gives a choice of seed mixes and is generally less expensive than turf.

New turf gives immediate grass cover and can become usable sooner, once rooted. It still needs careful ground preparation, watering during establishment and time without heavy traffic. See the RHS guide to laying turf.

Before spending money, find the reason your lawn is struggling. Drought, compacted soil, shade, pets, buried rubble, pests and diseases can create similar looking patches. A successful repair starts by addressing the cause.

When is the best time to renovate a lawn in the UK?

Early autumn is generally an excellent time to sow grass seed because soil warmth and reliable moisture support establishment. Mid spring is another useful window. Repairing thin or worn areas is best done when the grass is actively growing and the soil is moist rather than saturated.

Conditions vary across the UK. In Scotland, northern areas and exposed gardens, the reliable autumn sowing window can close earlier than in southern England. Late October sowing is therefore much less dependable in a cold garden than in a sheltered southern site. Check soil temperature, frost risk and drainage rather than relying on a calendar date alone.

Turf is normally best laid from autumn through early spring when the ground is workable, not frozen or waterlogged. Hot, dry conditions increase the watering needed to establish it. Our planner gives broad regional guidance, not a weather forecast or a guaranteed germination date. The RHS guide to autumn lawn care explains the main seasonal jobs.

Scarifying, aerating and top dressing explained

• Scarifying: Rakes out excessive thatch and moss. Use it when there is a genuine build up and enough active growing time for the grass to recover. A light rake may be all a thin lawn needs before overseeding.
• Solid tine aeration: Uses a garden fork or solid tines to create holes and ease some compaction. Work when the soil is moist but not waterlogged.
• Hollow tine aeration: Removes small plugs of soil and is particularly useful for compacted clay soils. Avoid working saturated ground.
• Top dressing: Adds a thin dressing that is worked into the grass or aeration holes. It is not a substitute for fixing deep depressions or persistent drainage problems.

Not every lawn needs all these treatments. The planner recommends work based on the problems you report and warns when the soil is frozen, extremely dry or waterlogged. As the RHS autumn lawn guidance explains, maintenance tasks should be chosen to suit the lawn rather than carried out automatically every year.

Aftercare matters as much as sowing

New seed needs contact with soil and moisture to germinate. If there is no useful rainfall, water gently to avoid washing the seed away. Keep traffic off repaired patches until the grass is established and delay the first cut until the seedlings are tall and strong enough.

New turf needs good soil contact and sufficient moisture while rooting. Do not assume that an instant green surface is ready for immediate family use. Once established, most lawns can recover from normal summer browning without routine watering, and regular feeding is not essential for every garden.

A wildlife friendly lawn is another valid choice. Allowing clover and low growing flowers, mowing less frequently and leaving some less formal areas can reduce maintenance and support wildlife.

Frequently asked questions

How much grass seed do I need for 100 m²?

At 35 g/m² a new 100 m² lawn needs 3.5 kg before allowances. At 25 g/m², it would need 2.5 kg. Always use the sowing rate on your seed packet, as different mixes have different recommendations.

Should I scarify before overseeding?

Only when you have enough thatch or moss to justify it. Lightly raking the surface can help seed make contact with soil, without subjecting an already stressed lawn to unnecessary aggressive scarification.

Can I sow grass seed in October?

Sometimes, especially in warmer parts of the UK when the soil remains mild. In colder or exposed areas, germination and establishment become less reliable as the season progresses. Wait for a suitable growing window rather than sow into cold or waterlogged ground.

How much turf should I order?

Measure the area, add a sensible cutting allowance and divide by the coverage of your supplier’s turf rolls. Enter the actual roll dimensions into the planner. Curved edges and complex shapes may need a larger allowance.

How thick should lawn top dressing be?

A routine dressing is thin enough for the existing grass to remain visible. The amount depends on the product, the purpose and whether you are filling aeration holes. For deeper hollows, correct the soil level rather than burying existing grass under a thick layer.

What should I do if my lawn is waterlogged?

Wait until standing water has drained and the soil is workable before renovating. Persistent waterlogging may need more than aeration, including changes to drainage or the garden layout. Read the RHS waterlogged lawn advice.

Do I need moss killer, weedkiller or fertiliser?

Not necessarily. Many lawns can be improved by addressing shade, compaction, mowing and growing conditions. You can also choose to keep moss or lawn flowers. The planner does not calculate pesticide applications and only calculates fertiliser from a product rate you enter yourself.

Can I save the plan and use it on my phone?

Yes. The planner works on mobile and desktop. Saved projects stay in your current browser on that device rather than syncing to an account. You can export a shopping list and print a plan to take outdoors.

More free GHUK planning tools

• Garden Materials Calculator for compost, topsoil, gravel and bulk material orders.
• Bulb Planting Planner for planning spring bulbs in beds and lawns.
• Hedge Planting Planner for setting out a new boundary hedge or wildlife hedgerow.
• Garden Tools and Calculators to browse all our free planning tools.
• What to Do This Month for seasonal gardening jobs across the UK.