Home › Guides › Lawn feeding, weed and moss control: a year-round calendar
Maintaining a healthy lawn requires planning treatments throughout the year: feeding at the right seasons, controlling weeds and moss when conditions favour them, and working within water restrictions that may apply to your area. Understanding what each treatment does, when to apply it, and what regulations govern professional applications ensures your lawn stays in good condition year-round.
Spring feeding and growth promotion: March to May
Apply a spring or summer lawn fertiliser in mid-spring, usually late March to April, while the lawn is actively growing. Spring feeds are high in nitrogen (N), typically formulated around 20–5–10 NPK or higher in nitrogen. Nitrogen is the engine of leafy growth; it powers grass shoots and gives the lawn its deep green colour. The RHS recommends applying spring feed at the manufacturer’s recommended rate once and waiting for natural rainfall or watering to activate it.
Spring is also the best time to address moss and assess the need for weed control. Early moss is thinner and easier to remove than established autumn moss.
Moss control: removal and prevention: spring and autumn
Effective moss control begins with removing existing moss and preventing recurrence. The RHS recommends physical removal through scarification in autumn (September to October) or spring (March to May), when grass is actively growing and can recover well. Use a spring-tined rake on small lawns, or hire a mechanical scarifier for larger areas. Rake vigorously in two directions to remove loose moss and thatch, then collect all material for composting.
For persistent moss problems, the RHS advises applying an HSE-approved moss killer product (many contain bacteria-based formulations or other approved active ingredients) in autumn or spring. Always follow product label instructions carefully. However, moss will only return unless the underlying conditions that favour it—poor drainage, compacted soil, shade, or acidic soil—are addressed. Aeration, improved drainage, and a programme of regular feeding and mowing to encourage strong grass growth provide the best long-term defence against moss.
Weed control: selective herbicides and regulations
Selective herbicides kill broadleaf weeds (dandelion, clover, plantain) while leaving grass unharmed. They are available in two categories: amateur products, formulated for homeowners with straightforward application and minimal toxicity, and professional products, which are more potent but must be applied only by someone holding a valid UK PA1 and PA6 pesticide application certificate (or equivalent).
If you hire a contractor to apply herbicides, verify that they hold the required certification from an HSE-recognised awarding body. The HSE requires that all professional applicators of plant protection products maintain records of every application for three years and take reasonable precautions to prevent harm to adjacent areas, public spaces, and vulnerable groups. Professional applicators must also have their equipment inspected within five years of purchase, then every three to six years depending on type.
For do-it-yourself weed control, amateur selective herbicides are available from garden centres and online retailers and are safe for homeowners to apply following the label instructions.
Summer care and watering restrictions: June to August
Most established UK lawns require no watering; the RHS confirms that rainfall from autumn to spring is usually sufficient for healthy growth, and established lawns will recover once rain returns even if they brown during drought. Newly seeded or turfed lawns do need regular watering—every 7–10 days in dry weather—until establishment is complete, typically 6–8 weeks.
However, water restrictions (hosepipe bans) may apply to your area during summer months. As of 2026, multiple water companies across England have implemented Temporary Use Bans affecting over 27 million people. These bans prohibit using a hosepipe, sprinkler or pressure washer connected to mains water for watering gardens. Watering cans, buckets and water butts remain allowed. Check your local water company’s website to confirm whether restrictions apply to you. Breach of a hosepipe ban can result in a fine of up to £1,000.
Autumn feeding and hardening: September to November
Apply an autumn lawn fertiliser in September or October. Autumn feeds are high in potassium (K) and phosphorus (P), typically formulated around 3–5–12 NPK or with potassium as the dominant nutrient. Potassium strengthens cell walls, helping grass resist frost, disease and foot traffic. Phosphorus supports root development, and strong roots mean better drought tolerance and faster recovery from wear.
Never apply leftover spring or summer feed in autumn; high nitrogen stimulates soft, lush growth that is vulnerable to frost and fungal disease. Use autumn-formulated feeds only.
Understanding NPK on the packet
Every lawn fertiliser label shows three numbers: nitrogen (N), phosphorus (P), and potassium (K), always in that order. A spring feed of 20–5–10 means 20% nitrogen, 5% phosphorus, 10% potassium—heavy on nitrogen for leafy growth. An autumn feed of 3–5–12 reverses the balance, emphasizing potassium for hardiness. Knowing these ratios helps you avoid applying the wrong feed at the wrong time; selecting the correct seasonal formula matters more than the brand.
Winter: minimal or no treatment
Most lawns enter dormancy from November through February and require no feeding or treatment. If mild weather persists and grass continues growing, mowing on a high setting is acceptable, but feeding is unnecessary. Avoid applying any treatments during frozen or waterlogged conditions.
Key points
- Apply spring feed (high nitrogen) in late March to April and autumn feed (high potassium) in September to October; never use leftover spring feed in autumn
- Remove moss through scarification in autumn or spring; use HSE-approved moss killer products if needed, following label instructions
- Address underlying causes of moss (poor drainage, compaction, shade, soil acidity) through aeration and improved lawn care to prevent recurrence
- Use amateur selective herbicides yourself following label instructions, or hire a contractor certified by the HSE with PA1 and PA6 qualifications
- Check your local water company’s website in summer for hosepipe bans; watering cans are allowed even when bans are in force
- Most established lawns need no watering; only newly seeded or turfed lawns require regular watering until establishment