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Lockdown Project Guides: Grow Your Own Marvellous Mushrooms

Growing your own mushrooms using a kit is easy and our Windowsill Mushroom Kits mean anyone can grow mushrooms indoors. Whether you’re a full-time gardener or beginner, this handy kit includes a base tray, lid, pre-spawned substrate and easy to follow instructions. You just need to right growing conditions and a little patience, and you’ll be harvesting fantastic fungi in a few weeks!

Suttons has Windowsill Mushroom Kits for many different mushroom varieties but let’s get started with popular White Button mushrooms, which hold their flavour and are delicious when added as a pizza topping, marinated or grilled.

Here’s Your Guide to Achieving Fantastic Fungi in 10 Simple Steps

Difficulty:       Moderate

Duration:       15 minutes (plus grow time)

You Will Need

  • White Button or Chestnut Mushroom Windowsill Kit, containing: base tray, colonised substrate, a bag of cover compost and a plastic lid.
  • A small knife.
  • A bowl containing 0.5L of water.
  • A small watering can.
  • A thermometer.
  • A plant mister or spray bottle.


Prepare your mushroom kit

  • Step 1: Open your kit as soon as it arrives. Remove the bag containing the cover compost and store it in a cool place.
  • Step 2: Put the lid on the base tray (containing the substrate) and keep at a temperature of 20-25°C for at least 4 days. After this period, the substrate will have turned completely white with fungus (mycelium).

Mushrooms are fungi, which mean they grow from microscopic spores (not seeds).  These spores develop under the ground, so most of the time when you are watching for signs of growth in your kit you see nothing happening at all!  But under the surface tiny filaments called hyphae are spreading to form a mass called a mycelium – it is the fruit of this mycelium that we eat as mushrooms. 

Suttons windowsill mushroom kit contents
Kit contains a bag of cover compost, base tray (with substrate) and lid

After 4 days…

  • Step 3: Take the bag containing the cover compost and punch ten holes in each side using a knife.
  • Step 4: Place the bag containing the cover compost in a large bowl containing 0.5 litres of water – leave for 20 minutes (now’s a good time to go and fetch your base tray containing the substrate). Remove the bag from the bowl, open it up and spread the cover compost evenly and loosely over the substrate.
Place the punctured bag of cover compost in a bowl of water
  • Step 5: Now put the tray aside with the lid closed for 5–8 days, at a temperature of 20–25°C. In this period, the mycelium will grow through the layer of cover compost to the surface.
  • Step 6: Once the cover compost is covered with white mycelium, put the tray in a cooler space of 15–18°C. Make sure that the surface of the cover compost does not dry out by regularly mist spraying with a plant spray.
Compost covered with white mycelium

Wait for Mushrooms to Emerge…

  • Note: To begin with, nothing seems to be happening but then, by peering closely at the soil, you will see tiny mushrooms just under the surface. They will gradually peep though when the mushrooms were about the size of a shirt button. Once above the surface they soon get much bigger very quickly!
  • Step 7: The mushrooms first appear at the edges, and later in the centre. When a good number of pins appear, you can water the compost with a watering can instead of misting – the substrate and cover compost should be moist but not too wet.
Harvest by gently twisting and pulling


  • Step 8: Harvesting: Take a mushroom between your fingertips and carefully pull it out with a twist of the hand.
  • Step 9: Always water regularly to prevent the cover substrate from drying out between harvests.
  • Step 10: If all mushrooms have been harvested, water again and wait. After around a week, new mushrooms should appear and this process may repeat itself three times.
Why not make a delicious mushroom soup?

Final Top Tips

  • Start using your kit as soon as it arrives – they are unsuitable for storage.
  • Always wash your hands before you handle any of the kits – this will stop the spread of any germs from your hands getting into the substrate.
  • Carefully follow the instructions, maintaining the recommended temperatures at each stage for the best results.
  • Simply keep them moist and out of direct sunlight, and your first crop should be ready to pick in a matter of weeks.
  • You can expect at least another 2 pickings after that (full instructions are included in your kit).

What Next?

Video Grow Guide: Watch our mushroom growing guide video for detailed advice.

Try Some Different Varieties

If you’d like to try growing some more exotic varieties, we have Shiitake, Oyster and Lion’s Mane to tempt you, plus mushroom spawn and plugs so you can try a new growing method. Shop our full grow your own mushrooms range.

We hope you have enjoyed our lockdown project guides and be sure to stay tuned as there a plenty more to come this month! Next week is all about winter hanging baskets!

Share your gardening journey on social media pages as well keeping up to date with our latest offers and competitions.

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