STERILISED

Masters Mix Mushroom Substrate Sterilised

£15.50 inc. VAT

Our sterile Masters Mix substrate is a 50/50 mix of soybean hulls and hardwood fuel pellets, hydrated to the perfect field capactity with double carbon filtered water to ensure no nasty chemicals present to stunt the growth of the mycelium.

Our Masters Mix mushroom substrate blocks are renowned for their high yields and are sterilised on an extended cycle in our industrial autoclave for 3 hours at 126°C to ensure complete and thorough sterilisation.

Perfect for growing a wide range of mushrooms, and as they are completely sterile, they can be stored for many months (if not years before use). We offer our standard 100-day sterility guarantee on all sterile products.

5% gypsum is added to each block to help aid mycelial growth and ensure optimal levels of magnesium, calcium, sulphur, potassium and phosphorus.

We recommend using the sterilised substrate as soon as possible for best results.

UK-sourced hardwood sawdust
Devoid of chemicals
Sealed before sterilisation
100-day sterility guarantee as standard

Professionally produced and sold in genuine Unicorn substrate bags, 3kg in weight.

Please review the drop-down sections below before placing your order, especially product lead-times if stated.

+ Lead Times

Whilst we often maintain a small inventory of most items for immediate dispatch, often, items that are freshly produced, high-volume, or made-to-order may require additional time before they can be shipped.

This additional time is referred to as the ‘lead time’ or production time. Please consider this when placing your order.

The estimated lead times for this product are listed below:

Orders less than 12 units: 1 week
40 units: 2 week
200 units: 3 weeks

Please contact us if you require larger orders sooner; we may be able to expedite your order for a small fee.

+ Technical Information

Available in 3kg bags.
Genuine Unicorn Filtered Bags.
100-day Sterility Guarantee
Made using double-filtered water, passed through an activated carbon filter.
Horticultural gypsum adds essential minerals and trace elements to support vigorous mycelial growth.
We use these ourselves in our mushroom production facility.
Sealed with a 6mm sealer before being sterilised in an extended autoclave sterilisation cycle.
Suitable for numerous mushroom species.

+ Shipping & Returns

FREE SHIPPING AVAILABLE ON ALL ORDERS OVER £50

Orders are typically dispatched on the same or next working day. However, please allow up to 3 working days for dispatch, plus any additional product lead times, especially during busy periods.

We ship our products in plain, unbranded, reinforced cardboard boxes with ample internal protection.

Our shipping couriers may leave parcels with a neighbor or in a safe place if no one is home to receive them. To prevent this, please select the designated signed-for service at checkout and ensure you are available to receive the parcel. Otherwise, the package will be held at your local sorting office or returned to us. Please note that we cannot be held responsible for lost, stolen, or missing parcels if the signed-for service is not chosen at checkout.

Larger orders that require multiple boxes will automatically be upgraded to DPD Local shipping, as they support multi-parcel shipments. Extremely large or heavy orders may need to be dispatched via a pallet.

If items are returned to us due to a failed delivery, a redispatch or restocking fee may apply. Please ensure that any held packages are collected from your local sorting office within 2 weeks to avoid them being returned.

We highly recommend upgrading to the ‘DPD Express Tracked’ service at checkout, as we find it to be the fastest, safest, and most reliable option. Please note that Royal Mail may occasionally experience delays in their sorting offices.

For more details, please refer to our shipping, returns and replacements policy.

+ Quantity Discounts 🔥🔥

Quantity	Item Price	% Discount
1	£15.50	-
2 - 4	£14.88	4%
5 - 9	£14.11	9%
10 - 24	£13.33	14%
25 - 49	£12.56	19%
50+	£12.40	20%

OFTEN MADE TO ORDER - May be subject to lead times above

Masters Mix Substrate (Sterilised) FAQ

Answers to frequently asked questions.

How will my product be packaged and shipped?

We invest significant time and resources to ensure our parcels are securely packaged and reach you safely and undamaged.

If your item requires a box, it will be shipped in a discreet, plain, sturdy, double-walled cardboard box of appropriate size, with unbranded packaging tape and ample internal protection to prevent damage during transit. While accidents are rare, they can occasionally happen.

Smaller, sturdy, and lightweight items will be sent in plain, unbranded padded envelopes.

All pallet orders are professionally strapped, wrapped, and equipped with corner protectors.

We also strive to minimize excessive packaging to help protect the environment.

Scroll down to see a section on our Shipping & Returns info, with links out to our policies

Can you do custom and bespoke orders?

Yes, we can accommodate your needs for any custom orders, substrate / grain mixes, special requests etc. Generally speaking, anything which is considered to be a custom order will have a bespoke price. Please contact us to discuss options.

Do you accept cash payments?

As an online-focused business, we prefer digital payments. However, for orders over £500, we do accept cash payments. Please contact us to process your order and arrange collection.

Can I collect my order from your facility?

We do not provide a standard collection service for orders under £500. If your order exceeds £500 and you wish to collect it, please contact us. Please note that, due to our insurance policies, we are unable to allow public access to our warehouse or offer tours of our facilities.