Mushroom 'Brown Cap Button' (Portabella)Agaricus bisporus

Hardy Annual

What is Hardy Annual?
A plant that completes its entire life cycle (growth, reproduction, death) in one season.
Capable of withstanding outdoor winter temperatures down to -15C.


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Please note: This product cannot be delivered outside the United Kingdom.

Height Up to 10cm (3.9in)
Spread Up to 12cm (4.7in)

Hardy Annual

kitchen gardenwoodland garden

Dappled shadeShade

Harvest Months

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Why not try something a little bit different, and grow your own mushrooms? Mushroom growing may seem complicated but our easy to grow kits are provided with detailed instructions and require no specialist equipment.

Brown Cap or Portabella mushrooms are an old fashioned variety. Its firm texture and enhanced nutty flavour offer alternatives to white button mushrooms.

Grain spawn is available all year and enables growers to follow traditional methods of growing on composted manure. Using this method mushrooms may be grown outdoors or indoors in controlled conditions. Sow outside from spring to August, or sow indoors with an even temperature of around 16C (50F), and not below 10C or above 20C. Supplied with full cultural instructions.

How to grow mushrooms

100g mushroom spawn (KC4794)

How to Grow


Mushrooms can be grown outdoors in neglected lawns and around compost heaps. They are most successful in soils that are rich in organic matter. Lift an area of turf and loosen the soil beneath, adding extra organic matter if required. Spread the mushroom compost over the soil surface and replace the turf. Turf should be kept moist though not waterlogged. When growing mushrooms outdoors, fruiting will depend entirely upon weather conditions.


Button mushrooms can be grown in a mushroom box or bed, on compost made from well prepared horse manure. Mushroom beds and boxes can be established in cellars, sheds, or garden frames, and should be 25cm (10") deep. Tightly pack mushroom beds with prepared compost and scatter the spawn across the surface, before covering with damp newspaper. After 3 weeks, the compost will be colonised by mycelium. Remove the newspaper and cover the compost with a 2.5cm (1") layer of casing, mixed from garden soil, peat and lime. Mushrooms will begin to develop 3 to 5 weeks after adding the casing layer.

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Maintain a moist, humid atmosphere as mushrooms develop by watering with a fine rose watering can or with regular misting. Harvest mushrooms by twisting the cap until it comes away from the compost. Caution: Some people are allergic to mushrooms or mushroom spores and others may become sensitised by high concentrations of spores.

Seeds and garden supplies will normally be delivered within the time period stated against each product as detailed above. Plants, bulbs, corms, tubers, shrubs, trees, potatoes, etc. are delivered at the appropriate time for planting or potting on. Delivery times will be stated on the product page above, or in your order acknowledgement page and email.

Orders for packets of seed incur a delivery charge of £2.99.

Orders which include any other products will incur a delivery charge of £6.99.

Where an order includes both packets of seeds and other products, a maximum delivery charge of £7.99 will apply - regardless of the number of items ordered.

Large items may incur a higher delivery charge - this will be displayed in your shopping basket.

Please see our Delivery page for further details, and more information on different charges that may apply to certain destinations.

For more information on how we send your plants please visit our Helpful Guide on plant sizes.

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Mushroom 'Brown Cap Button' (Portabella)

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