Spawn is the living mycelium, grown onto a substrate. At Mushrush, our mushroom spawn is grown on sorghum grain. Spawn is critical for all mushroom growing operations. They are the seeds that form the foundation for farming mushrooms.


Substrate is a material that mycelium can grow and establish itself on. The nutrients, moisture and energy mushrooms need to grow and produce fruit are found in the substrate. It is essential for mushroom growing.

Once you have decided on what mushrooms you want to grow and done a little research, you’ll have an idea of what spawn and substrate (mushroom seed and mushroom food) you’d like to buy. You’ll find a great commercial range of popular exotic gourmet mushrooms in our on-line shop, under Spawn + Culture.  If you’re looking for the magic mushroom kind, you’re not going to find it here at Mushrush.

We believe in a ‘self-sustaining’ way of farming mushrooms. Unless you want to throw large sums of money into your project, find out what substrates you have easily or cheaply available to you in your area. Some examples of uncomposted substrates are: straw, sawdust, mielie cobs, paper, cotton waste, coffee grinds or a combination of any of these. Composted substrate would be straw composted with chicken manure.

Because spawn is the foundation of mushroom growing it is crucial that you buy quality spawn and from a reputable spawn maker.

Quality spawn is produced in sterile laboratory conditions to eliminate infection in the mycelium and ensures a healthy rapid growing product. Great spawn is made from fresh, well-maintained cultures.

Reputable spawn makers strive to produce top quality spawn by employing good laboratory practice. Having an in-depth knowledge of mycology and international training is an added advantage.

Now, how much spawn to buy? We make our spawn fresh, to order and in 2 kilogram bags. This is recommended for first time growers or the farmers market or local restaurant supplier mushroom farmers.

As a very basic guideline and depending on your substrate, here is an idea of spawn:substrate:yield ratios.

For a lime soak method – 2kg spawn:20kg substrate:10-20kg yield.

For a steam pasteurisation method (making grow logs) – 2kg spawn:200kg substrate:100-200kg yield.

These are very rough guidelines because other conditions also contribute positively or negatively to your yield. Experimenting in growing mushrooms is inevitable.

We recommend ‘over night’ delivery for spawn. Store the spawn in the fridge and try to use it within 2 weeks. The older the spawn the lower the yield potential.

Depending on what you would like to grow your mushrooms; sawdust, straw, paper waste etc will help you decide what production system to use. Straw and lime are simple and cost-effective.
If you are using straw we recommend our Elm A and PL strains


  • Rookie ‘Roomer Mushroom Grow Kit

  • Hydrated lime

    Hydrated Lime – 1kg

  • Pink oyster mushrooms

    Pink Oyster Mushroom Spawn – 2kg

  • King Oyster Mushroom

    King Oyster Mushroom Spawn – 2kg