Rye Grain (Organic, Sterilised)

(6 customer reviews)

£11.75£16.00 inc. VAT

Our premium sterile Rye Grain Bags are made fresh each week from UK-sourced, 100% organic, pesticide and fungicide-free rye grain. Perfectly hydrated and expertly processed to ensure perfect sterility, ready for spawn production and bulk mushroom cultivation.

Each bag is made from Genuine Unicorn filtered mushroom bags Manufactured in the U.S.A., with each one having an injection port which is welded into the bag (these are not cheap, flimsy, thin and faulty Chinese knockoff bags with makeshift stuck-on injection ports to save cost, tut tut…).

Our bags are uncompressed and sealed with our industrial 6mm heat-sealing machine. Each bag has an integrated autoclave sterilisation indicator strip and a unique bag batch number tag.*

We are masters in grain production, having produced and sold over 100,000 sterile grain bags over the past 6 years, supplying to commercial mushroom farms and hobby cultivators alike, we use only the best supplies to make our products. We stand behind our name. If you buy cheaper bags, you’ll get more contamination; don’t learn the hard way! Quality costs, but it saves in the long-run. Each bag comes with a 30-day 100% Sterility Guarantee.

Fresh grain batches are produced weekly to meet demand and could be subject to the lead times below.

Please familiarise yourself with the FAQ's & drop-down sections below before placing your order.

+ Lead Times

For freshly produced, high-volume or ‘made to order’ items there could be an additional delay in dispatching your order, this is known as a ‘lead-time’ or production time. Our estimated lead times for this product are shown below:

  • Less than 48 units: up to 1 week
  • 120 units: up to 2 weeks
  • 480 units: up to 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
  • Full instructions included (link below).
  • Made from certified UK-grown organic grain.
  • Genuine Unicorn Filtered Bags – 0.75kg, 1.2kg & 1.5kg. All with injection ports.
  • Triple-washed to remove chaff, soaked overnight and boiled to a consistent moisture content of 55%.
  • 8% horticultural gypsum is added to help keep grains separated and to add essential minerals and trace elements to support vigorous mycelial growth.
  • Prepared in the same way we make our commercial spawn bags.
  • Bags can be used with all liquid cultures or spore syringes (though the risk of contamination is higher with spore syringes).
  • Suitable for beginners and advanced growers.
  • A liquid culture will need to be purchased separately.
  • Orders of 12 bags or more will most often be supplied without bag tag numbers or sterilisation indicator strips in order to keep prices low for our bulk customers.
  • Note that we cannot refund or replace already inoculated/used bags; please follow the included instructional guide (link also below) so you can self-validate the bag’s sterility before inoculation and ensure a successful grow.
+ Shipping & Returns


Orders are usually dispatched same or next working day, but please allow up to 3 working days for dispatch + any additional product lead times as sometimes we can get incredibly busy.

We package our products in plain, unbranded, reinforced cardboard boxes with plenty of internal protection.

Our shipping couriers may leave parcels with a neighbour or in a safe place if nobody is home to receive them. To avoid this from happening, please choose the designated signed for service at checkout (and ensure you are in to receive the parcel, else it’ll be held at your local sorting office or returned to us) – We cannot be responsible for lost, stolen or missing parcels where the signed for shipping service have not been selected at checkout.

Items which have have been returned to us due a failed delivery may be subject to a redispatch or re-stocking fee, so please ensure packages any held packages are collected from your local sorting office within 2 weeks to save them being returned.

We strongly advise people upgrade their shipping to ‘DPD Express Tracked‘ service at checkout as we find this to be the quickest, safest and most reliable service. Royal Mail do occasionally have delays in their sorting offices.

For more info, please see our shipping, returns and replacements policy.

+ Quantity Discounts
Quantity Item Price % Discount
1 £11.75£16.00 -
2 £11.16£15.20 5%
3 £11.05£15.04 6%
4 - 5 £10.22£13.92 13%
6 - 7 £9.40£12.80 20%
8 - 11 £9.17£12.48 22%
12 - 23 £8.58£11.68 27%
24 - 47 £8.23£11.20 30%
48 - 96 £8.11£11.04 31%

To allow us to serve all of our customers fairly, we are only able to process a total of 96 made to order products directly through our website per customer/week.

For larger quantities and wholesale enquiries, please contact our sales team so they can give you the best price, lead-times and delivery information.

Purchasing Disabled

Due to recent flooding in our warehouse and processing facilities, we're only accepting orders for a limited number of our products, which are available for purchase on our eBay store.

£11.75£16.00 inc. VAT

Purchase one of these today to earn ~11-16 POINTS worth £0.55-£0.80 to redeem on your next order.
Purchase one of these today to earn ~11-16 POINTS worth £0.55-£0.80 to redeem on your next order.
114 people have added this item to their basket in the past 24 hours.
Shipping & Returns info | Free Shipping Available Over £90 🚀
⇓ More product information below ⇓

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5-Star Customer Testimonials

Over 2,300 rave reviews and counting! Here's a random selection (different on every page)...

Every single bag worked absolutely fine from the second it innoced, it had healthy white myc eating at it in no time! And getting the bag to fruit could not be any simpler! Amazing bags! Will always come back for sure! Thanks, Ben.

⭐⭐⭐⭐⭐e chalk on Google

These guys are great and definitely worth the coin! I don't get grow bags from anywhere else now but have found these have the perfect ratio of contents and have never been contaminated so it is clear its very sterile.

⭐⭐⭐⭐⭐Danny Darka on Google

Very happy with the products from this store. Purchased on etsy and had a good experience and will definitely come back again

⭐⭐⭐⭐⭐Isaac Antoine on Google

Very pleased with my recent order. Very high quality product with fast delivery and neat packaging. I'm seeing Great result, especially following the well written instructions. Also received quick and clear responses with any queries I had. Definitely will come back to order more soon. 😊

⭐⭐⭐⭐⭐Antoni Kurpiel on Google


Answers to frequently asked questions.

Do you accept cash payments for larger orders?

Yes, we accept cash payments, but would require a none-refundable 20% deposit to be paid to add your order to our jobs list. The remaining balance of your order can be paid in cash on collection (we don't accept cash in the post). Once your order is ready, it will need to be collected and paid for in full within 3 weeks, else we reserve the right to re-sell your order and your deposit will not be refunded.

To pay a cash deposit, please process your order online as normal, select whichever payment method you wish, and use the following discount code at checkout to take 80% off the order, leaving a 20% deposit: cash-deposit-20

Note that this discount code is only to be used to leave a 20% deposit for cash collection orders only. Please make contact with us before to discuss lead-times and collection windows.

There is a minimum order value of £500 to pay a cash deposit.

How will my product be packaged and shipped?

We put a lot of time and money to ensure our parcels are sent out so that they reach you safely and undamaged.

If your item will go in a box, it will be sent out in a discreet, plain, sturdy, double-walled cardboard box of appropriate size, with no branding packaging tape and plenty of internal packaging protection to avoid any damage during transit (though sometimes accidents can happen, but it's rare).

Smaller items which are sturdy and light will be sent out in plain, unbranded, padded envelopes.

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

We try to minimise the use of excessive packaging where can, to help save mother nature and all her gloriousness.

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

Can I collect my order from your facility?

For larger orders that would otherwise typically go on a pallet, that's fine, but generally speaking, we'd prefer to ship to an address. Please contact us before placing your order if you want to collect your order to see if we can accommodate it. We are based in the Forest of Dean. We've got a busy warehouse where we do our thing, but we don't (yet) have a shop.

What is included with my grain bag purchase?

Each order comes with the quantity of bags ordered, one instructional guide and one set of alcohol wipes per order. Please leave a note at checkout if you require additional instructional guides or alcohol wipes. You must purchase a liquid culture of your chosen mushroom strain separately.

Where can I download a copy of the Instructional Guide

A copy of our instructional guide can be downloaded here: Sterilised Grain Bag Instructions.

Note that a printed hard copy of the instructional guide will be included with your order.

What else do I need to purchase to grow mushrooms?

There are numerous ways of growing mushrooms, and will depend on your experience, available equipment and time availability. At a minimum, you will need to purchase the following in addition to your grain bag(s):

Liquid Culture – A mushroom liquid culture of the strain you want to grow. (You may also use a spore syringe, but we do not recommend it due to the higher risk of contamination)

Substrate – You will need to decide on the most suitable substrate for the mushrooms you are growing. Substrate is required to mix with colonised grain spawn to ensure a successful yield.

Fruiting Chamber (optional) – Different strains of mushrooms like to grow in different ways. Popular set-up examples are a monotub, a shotgun fruiting chamber, a ‘martha’ style humidity chamber where mushrooms are grown on trays or blocks, or even on suspended straw columns in a temperature and humidity-controlled room.

If you’re looking to grow fruit mushrooms in the bag, our All-in-One mushroom growing kit will allow you to do just that.

We highly recommend researching what mushroom cultivation method will best suit you. A good resource is the ‘Shroomey forum’ – it has a wealth of cultivation advice on growing most mushroom strains and an active forum of cultivators who can share their experience and knowledge.

How much liquid culture do I need to innoculate one grain bag?

We recommend using 1-2ml of liquid culture per 1.5kg grain bag (or approximately 0.5-1ml for a 750g bag).

What sizes / volumes are your grain bags?

The approximate sizes and volumes of our grain bags are as follows:

  • 1.5kg – 15cm x 12cm x 12cm (approximately 2.16 litres or 2.28 quarts (US measurements)
  • 1.2kg – 15cm x 12cm x 10cm (approximately 1.8 litres or 1.9 quarts (US measurements)
  • 750g – 11cm x 8cm x 11cm (approximately 0.97 litres or 1.0 quarts (US measurements)
How long can I store grain bags before inoculating?

We offer a 30-day, 100% sterility guarantee. We recommend leaving the bags for 1 week before inoculation so you can self-validate their sterility before use. Bags should be used within a month as, due to the nature of the filter on the bag, all bags will eventually succumb to contamination.

How should the grain bags be stored?

Sterilised grain bags are best stored at room temperature and left packed in the box they came in. This should stop excessive air or moisture escaping from the filter. Do not store them in the fridge or freezer, as this could cause excessive condensation in the bag, making your grain oversaturated.

Why do I need to leave the grain bag a week before using it?

We advise customers to leave their bags for 1 week before inoculation to self-validate the grain’s sterility. If there are no signs of contamination after a week, you can be assured that your bag is still perfectly sterile and ready to use. This can prove to be quite helpful should you experience contamination later in your grow.

Although we have multiple checks to ensure all the grain leaves us in perfect condition, on rare occasions, bags can become physically damaged in transit and subsequently contaminate. If this does happen, contact us, and we will arrange for a replacement to be dispatched. Please keep hold of the contaminated bag, as we might need more information from it before we can dispatch a replacement bag to you.

Note that due to the increased risks of contamination during inoculation, we do not offer refunds or replacements for bags that have already been used.

How is your grain produced?

To make our kits, we first triple-rinse the grain to remove dust or chaff. Next, we soak them overnight in a purified water + gypsum solution to partially hydrate the grains and allow any endospores to activate; adding gypsum provides additional nutrients to the grain, which supports healthy mycelial growth and also stops grains from becoming clumped together.

The partially hydrated grains are then slowly brought to a boil until they are hydrated to precisely 55%. We then quickly drain the boiling water and immediately distribute the grain on our outdoor drying racks, leaving it to steam off and cool.

This process removes any excess external moisture, resulting in perfectly hydrated grain, which is dry to the touch.

The resulting grain is then weighed into genuine Unicorn bags, double-sealed and processed in our industrial autoclave on an extended 123°C cycle for 3 hours to ensure all contaminants are killed off.

Once allowed to cool slowly, the bags are individually checked to ensure they are perfectly sterile and only then do we allow them to be dispatched to our customers.

How many grain bags have you produced to date?

For a number of years, we have provided sterilised grain and grow kits to hobby growers and commercial operations. While it’s difficult to put an exact number on it, we know it’s in excess of 100,000 grain bags. We have also sold countless sterilised substrate bags during our years in business.

How long will it take for the grain to colonise?

The time it takes for a bag to colonise fully will depend on many factors. The type and quality of your culture, whether you’re growing from spores or liquid culture, temperature, and even lighting conditions can affect colonisation rates.

While full colonisation takes 3 – 6 weeks on average, we would expect to see growth in a bag usually within a week if you’re using a high-quality liquid culture. Inoculating grain bags with spores can be notoriously unpredictable, with germination rates sometimes taking over one month alone.

What yield of mushrooms should I expect from a grain bag?

Different mushroom strains will have different yield expectations. Yields are generally calculated via biological efficiency. Some mushroom strains can produce five or more times that of others, so we can’t give a single answer.

I’ve found a small stone or white bit in my grain, what is it?

Whilst we do our best to remove all traces of foreign matter from our grain, on rare occasions, a very small stone might find its way into our bags from harvesting the grain. This will not affect the bag in any way, nor the colonisation of the mycelium.

Small white clumps within the odd bag will be clumps of gypsum, which we add to the grain.

Gypsum adds essential minerals to the rye grains and can be used as a supplement at almost all stages of mushroom production. Gypsum also aids in stopping the individual grains from sticking together in the bag, allowing for faster and more healthy colonisation – with less chance of contamination.

Why does the colour of the grain vary throughout the bag?

This is totally normal; discolouration can occur due to how the bags are loaded into the autoclave and left to cool after the sterilisation cycle.

Why does the grain appear wet with visible condensation showing in the bag?

Condensation forms in the bag due to fluctuating temperatures during shipping; this is totally normal. The grain can be mixed to allow it to reabsorb the condensation. It should be left for one week before inoculation. The included instructions provide more information on this.


No fuss Shipping, Returns & Guarantee.

  • We aim to dispatch orders within 2 working days (Monday-Friday)
  • Free shipping option for orders over £90.00 - Shipping Policy
  • No questions asked returns & refunds policy - Returns & Refunds Policy

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6 reviews for Rye Grain (Organic, Sterilised)

  1. Gareth

    Waited a week after they arrived and still contaminate free looking forward to get growing

  2. Sally-anne

    I don't really ever buy pre-hydrated and sterilised grain as grow on quite a small scale but I wanted to conduct side-by-side grow trials of various grains and measure colonisation times and resulting yields of each. Seemed like a no brainer. Haven't found any other company offering this, so thumbs up to you for doing so! I'm sure there are others out there who appreciate it as much as me. Leep up the good work!

  3. Jake

    Correctly hydrated and good quality but I think it's a little bit expensive for hydrated grain. Maybe if you're ordering in bulk or buying other supplies it makes sense but I just needed some grain as my pressure cooker packed in last week

  4. Jodie S.

    Perfect for the lazy mushroom head!

    On a more serious note, grains came well packaged and perfectly hydrated.

    I initially thought the grains were dry, so I contacted their support team who clarified that they weren't dry, but that they had been soaked and boiled in water containing gypsum, and when they are allowed to steam dry, there can be a fine residue white powder on the outside of the grain which can make it look dry. Paul from support said that I should try them, and if I wasn't happy he'd either send me a batch with no gypsum added or a refund! Needless to say, the grains were perfect, and I learnt something! Thanks for your support Paul. Have a nice rest of the day.

  5. Lee

    grain preparation can be a bit of ball-ache when you're trying to make a lot with a relatively small sized autoclave. This is the first time I've bought this in bulk, but for the price, it's not really worth me making it myself any more. That's capitalism for you (or maybe just scales of economy). Either way, I'm happy. Grains were perfectly hydrated, no standing water and mycelium is growing as expected. Mushroom cultivation has just got even easier…

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