A Practical Guide to Mixing Grass Seed with Topsoil for Overseeding

Overseeding is one of the easiest and most cost effective ways to breathe new life into a tired lawn. At Paynes Turf we often get asked: “Should I mix grass seed with topsoil when overseeding?”

The short answer is yes, when it makes sense and you use the right technique. Let’s start with the basics.

What Is Overseeding?

Overseeding means spreading new grass seed over an existing lawn. It fills in thin patches, boosts density and improves colour without the need to start from scratch. It is ideal for lawns worn by heavy foot traffic, pet use or seasonal stress.

Why Mixing Seed with Topsoil Can Help

1. Better Seed to Soil Contact
   Fine topsoil cradles each seed so it absorbs moisture and does not wash away in heavy rain.
   
    
2. Consistent Coverage
   A seed and soil blend spreads more evenly than seed alone, reducing bare spots.
   
    

3. Nutrient Boost
   Quality loamy topsoil brings organic matter and slow release nutrients to each seed’s roots.

   
   
    

When You Should and When You Should Not Mix

• Mix if you are overseeding large areas of thin or patchy grass or starting from mostly bare ground.
  
   

• Skip mixing if you only have a few small patches to fill in an otherwise healthy lawn. In that case, simply broadcast seed and rake lightly.

   

How to Mix and Apply

1. Choose the Right Grass Seed
   Match your existing turf: shade tolerant for shaded areas, drought resistant for sun baked spots or wear resistant for busy lawns. Browse our specialist blends here: Shop grass seed

1. Measure Your Blend
   Aim for one part seed to three or four parts topsoil by volume. For example, mix one kilogram of seed with three to four kilograms of topsoil.

1. Blend Thoroughly
   
    
   • For small lawns mix by hand in a wheelbarrow or large bucket
     
      
   • For larger areas use a clean compost or fertiliser spreader loaded with your seed soil mix

1. Prepare Your Lawn
   
    
   • Mow low and remove clippings
     
      
   • Lightly aerate or scarify to relieve compaction
     
      
   • Rake away debris so the surface is smooth

1. Spread the Mix
   
    
   • Aim for around three kilogrammes of mix per ten square metres
     
      
   • Roll lightly or press with a rake to ensure good seed to soil contact

1. Water and Aftercare
   
    
   • Mist daily until seedlings reach about five centimetres tall
     
      
   • Wait to mow until new grass is at least seven centimetres high and set your mower on its highest setting

Pro Tips and FAQs

Can I use any topsoil?
Use a well screened loamy mix without large debris.

What if I over mix?
Too much soil can bury seeds too deeply. Stick to the one to three or one to four ratio.

Is a mulch necessary?
A light straw mulch can help retain moisture but avoid thick layers that block sunlight.

How soon should I feed newly germinated grass?
After about six to eight weeks, apply a balanced feed to encourage strong root development.

Mixing grass seed with quality topsoil when overseeding boosts germination and gives new seedlings the nutrients they need to thrive. Ready to transform your turf? Visit Paynes Turf for garden soil delivery and specialist grass seed blends your lawn will love.