There’s no single “perfect” mowing height or schedule for every lawn. The ideal approach depends on grass species, season, and growing conditions such as weather, soil type, and how the lawn is used. However, the guidance below will help you achieve a healthy, resilient lawn in most situations.

Recommended mowing heights:

As a general rule, lawns should be kept between 25–40mm depending on the type of grass and time of year:

• Spring & autumn:
  Mow slightly higher, around 30–40mm, to encourage strong roots and recovery.

• Summer:
  Raise the cutting height to 35–45mm to help shade the soil, retain moisture, and reduce stress during hot or dry periods.

• Shaded or newly established lawns:
  Keep grass a little longer to improve photosynthesis and resilience.

Never remove more than one-third of the grass height in a single mow, as cutting too short weakens the plant and can lead to yellowing, moss, and weed invasion.

How often should I mow?

Mowing frequency depends on how fast the grass is growing:

• Peak growing season (spring & early summer):
  Every 5–7 days

• Mid to late summer (especially in dry conditions):
  Every 7–10 days, or less if growth slows

• Autumn:
  Every 10–14 days, reducing frequency as temperatures drop

• Winter:
  Only mow if necessary and when conditions are mild and dry

Correct storage plays a vital role in maintaining grass seed quality and ensuring strong germination. While grass seed is not highly perishable, poor storage conditions can significantly reduce its performance.

How to store grass seed correctly

For best results, store grass seed in:

• Cool, dry conditions – moisture and heat are the main causes of seed deterioration

• A well-ventilated area such as a garage or shed (not damp or humid)

• Original packaging or sealed containers to protect from moisture

• Raised off the ground to help prevent damp and discourage rodents

Avoid storing seed in greenhouses, conservatories, or areas prone to condensation, as fluctuating temperatures and humidity can reduce viability.

Grass seed shelf life

Grass seed does not expire immediately, but germination rates decline over time:

• Optimum performance:
  Use within the same season or the following season from the batch date (printed on the bottom of the box)

• After two years:
  Germination rates will begin to drop, meaning establishment may be slower or patchier

• Older seed:
  Can still grow, but results may be less reliable and higher sowing rates may be required

For the best and most consistent results, we always recommend using the freshest seed available.

Watering is one of the most important factors in successful grass seed establishment. During germination and the early growth stage, the soil must be kept consistently moist to allow the seed to sprout and develop strong roots.

Yes, you can mix different grass seed types or mixtures — and in many cases, it can be beneficial. However, it’s important to understand how different grasses behave to ensure the results meet your expectations.

Many lawn-based (or turf type) grass seed mixtures will be fine to mixture together. Perennial Ryegrass, Fine Fescues, & Bents are all grass species we use throughout our mixtures. 

The first mow is an important milestone for a new or overseeded lawn. Mowing too early can pull young plants out of the soil, while waiting too long can cause the grass to become weak or leggy.

You should carry out the first mow when:

• The grass has reached 5–7cm (50–70mm) in height

• Seedlings are firmly rooted and do not pull out when lightly tugged

• The lawn surface is dry and firm, not soft or waterlogged

This typically occurs 3–6 weeks after sowing, depending on grass species, temperature, and growing conditions.

Important Note: Remove only the top third of the grass blades on a first cut

In most cases, winter is not an ideal time to sow grass seed. Grass seed needs warmth and moisture to germinate, and winter conditions in the UK usually prevent reliable establishment.

Grass seed generally requires:

• Soil temperatures of around 8–10°C or higher to germinate

• Consistent moisture without freezing conditions

• Reasonable daylight and mild weather for early growth

However our Any Time Lawn Seed can be sown from just 3°C, due to the scientifically-proven grass cultivars.

If your lawn hasn’t established as expected, don’t worry — this is more common than people think and is usually easy to correct once the cause is identified. Most establishment failures are due to environmental conditions or aftercare rather than the seed itself.

Firstly, identify the issue - use our Common Lawn Issues page to help you find out whats wrong. Once indentified and the neccessary steps have been taken to resolve the issue, give your lawn an overseeding. This will encourage more coverage, denser swards and improve the visual apearance of your lawn. 

This varies within the product range, however majority of our mixtures will germinate within 2-4 weeks with optimum conditions. 

Poor weather or soil conditions can cause delay in the grass germinating. 

Yes lawn seed is perfectly safe to use around pets, children and birds.

The only product within the Johnsons range not safe, is the Quick Fix, due to it's inclusion of NPK 7-7-7 fertiliser, which we'd recommend keeping children and pets away from. Any direct skin contact wash throughly. If ingested or in contact with eyes, please seek medical advise. 

Seedbooster treatment used in Shady Place, Luxury Lawn & Lawn Thickener acts as a natural bird deterrent due to it's blue colour, however is not harmful if birds do still ingest the seed. 

Wildflowers vary greatly in height and growth habit, so there isn’t a single mowing height or frequency that suits all wildflower mixes. Some species stay low and delicate, while others grow tall and architectural, and mowing requirements depend entirely on the mix you’re using and the stage of growth.

• Wildflowers are not managed like lawns and should not be cut regularly

• Many wildflowers are intended to grow, flower, and set seed before any cutting takes place

• Cutting too early or too frequently can prevent flowering altogether

Because of this variation, the best approach is to:

• Check the specific guidance provided on each Johnsons wildflower product

• Follow the recommended cutting height and timing for that particular mix

• Only cut when advised — usually after flowering has finished and seed has set

Correct storage plays a vital role in maintaining wildflower seed quality and ensuring strong germination. While wildflower seed is not highly perishable, poor storage conditions can significantly reduce its performance.

How to store wildflower seeds correctly

For best results, store grass seed in:

• Cool, dry conditions – moisture and heat are the main causes of seed deterioration

• A well-ventilated area such as a garage or shed (not damp or humid)

• Original packaging or sealed containers to protect from moisture

• Raised off the ground to help prevent damp and discourage rodents

Avoid storing seed in greenhouses, conservatories, or areas prone to condensation, as fluctuating temperatures and humidity can reduce viability.

Wildflower seed shelf life

Wildflower seed does not expire immediately, but germination rates decline over time:

• Optimum performance:
  Use within the same season or the following season from the batch date (printed on the bottom of the box)

• After two years:
  Germination rates will begin to drop, meaning establishment may be slower or patchier

• Older seed:
  Can still grow, but results may be less reliable and higher sowing rates may be required

For the best and most consistent results, we always recommend using the freshest seed available.

Yes - some wildflowers can be sown in winter, but it depends on the type of wildflower mix and the species included. Unlike grass seed, many wildflowers are naturally adapted to experience cold conditions as part of their life cycle.

However, our current wildflower product range is for spring & autumn sowings only.

If your wildflowers don’t establish as expected, don’t worry — this is a common issue and is usually down to sowing conditions, soil preparation, or aftercare, rather than the seed itself. Once the cause is identified, most problems can be corrected.

Identify the issue: 

• Soil too fertile – grasses and weeds outcompete wildflowers

• Incorrect sowing time for the species in the mix

• Poor seed-to-soil contact

• Seed sown too deeply (wildflowers should be surface sown or lightly pressed in)

• Dry conditions after sowing, especially in spring

• Heavy rainfall washing seed away

• Bird predation removing seed

• Low light levels due to shade or competition

Most of these issues will require a reseed of wildflowers. For more guidance go to our wildflower management support page

This varies within the wildflower product range and within the flowers chosen for each mixture. 

Wildflower seed is generally safe to use around pets and children when used as intended. Wildflower mixes are made up of naturally occurring plant species and are commonly used in gardens, parks, schools, and public spaces.

Although generally safe, we recommend:

• Avoid ingestion – children and pets should not eat seeds or plants

• Wash hands after gardening or handling seed

• Supervise young children and pets around newly sown areas

• Keep unused seed stored securely and out of reach

Wildflowers are not likely resistant to dog urine and heavy wear and tear, so avoid any contact with the wildflower sown area where possible. 

Yes you can sow planters and pots with wildflowers. We recommend using only wildflower seed mixtures, and not using wildflower/grass seed mixtures. 

To sow wildflowers into a planter/pot, complete the same steps as specified on the 'How to sow wildflowers?' page

Consumer Department
DLF Seeds Ltd
Thorn Farm
Evesham road
Inkberrow
Worcestershire
WR7 4LJ

Email: info@johnsonslawnseed.co.uk

Tel: 01386 791113

No - Johnsons Lawn Seed only supplies garden centres and retailers. We recommend visiting your nearest stockist or ordering from one of our trusted online retailers.

Yes - please contact info@johnsonslawnseed.co.uk or call 01386 791113

Please visit our trade site, which contains the details to your local Johnsons sales agent.