Microwavable Rice Bag with Mushrooms Growing out of Bottom with Blurred Confetti Background

Spiderman Tek: A Grow Guide For Beginners

Microwavable rice sachets are the key to Spiderman Tek, a growing method that's increasingly popular with new cultivators.

DoubleBlind Mag

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Published on
Updated June 5, 2024

Disclaimer: this article covers a legal theme.

Purported to have come first from a biochemist-turned-psychedelic-coach and facilitator going by u/shroomscout on Reddit back in 2019, Spiderman Tek (also known as Uncle Ben’s Tek) is effectively a brown rice tek, just like the more well-known PF Tek. The genius of Spiderman Tek is that it simply uses a widely available version of partially wet rice that’s sort of like a ready-made grain bag: The microwavable rice sachet.

Image of Uncle Ben Microwavable Rice Bag

This rough-and-ready growing method has surged in popularity in the last five or six years. While it keeps setup costs low, the downside is that it’s got a high failure rate and doesn’t offer as much control as a more tried-and-tested method like PF Tek. 

When this tek was first proposed back in 2019, it received mixed reviews. More experienced growers regarded it as lazy, bypassing a lot of the established and well-tested mycology techniques. However, seeing how it’s helped so many growers get a decent crop of mushrooms and having tried it out ourselves, we can’t deny its value—especially for beginners. 

READ: Why You Should Grow Your Own Mushrooms

Spiderman Tek: Spawn to Bulk Basics 

Brown rice is one of the nutrient sources used in other teks, and the Spiderman Tek simplifies everything by using ready-made rice bags in which the rice is already prepped. There’s no need for sterilizing the substrate as the bags are vacuum sealed. The spore syringe is sterilized over a flame, and the hole you’ll make in the bag is covered by micropore tape. The fact that this is now the go-to method for new growers is a testament to how simple it really is.

Colonization Time 

Bags can take around two to three weeks to reach full colonization, but if the conditions are perfect, it might happen quicker. At this point, most growers mix their rice into a clean monotub with some prepared bulk substrate to improve yield. Once you’ve transferred the colonized rice to the bulk substrate, it might take another two to four weeks, depending on your mixing ratio. In total, mushrooms could appear as soon as one month from beginning this tek, but don’t be disheartened if it takes a few weeks longer.


Once your tubs are fully colonized, you can introduce them into fruiting conditions. The specifics of this process depend on your grow setup, but essentially you’ll need to allow fresh air exchange (by loosening the lid or uncovering airholes) and mist a few times per day. If you’ve got everything right, you’ll begin to see small white dots—called hyphal knots, primordia, or pins—forming across the surface. These will quickly begin growing into full sized mushrooms in a day or two, so keep a close eye on them.

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The amount of mushrooms you can grow from Spiderman Tek can vary depending on a whole range of factors, from bulk substrate used to the genetics of the mycelium itself. However most growers consider a typical rice bag to produce around 1¾ to 5¼ oz (50 to 150 g) of fresh mushrooms, or around ⅕ to ⅗ oz (5 to 15 g) after drying.

Supplies You’ll Need to Get Started

For this method you use the kind of “instant” brown rice bags that cook in the microwave for two minutes. The precooked rice is no longer dry, meaning it offers up both the nutrient source and the moisture that mycelium needs to grow, and it is sterilized to be shelf-stable. Ensure your bags contain brown/whole grain rice only, with a tiny percentage of oil added; any salt present will kill off the mycelium. 

You’ll need:

For the rice bags:

  • 10 bags of microwavable instant brown rice

For inoculation:

Image of Uncle Ben, Syringe, Tape, Rubbing Alcohol
  • A still air box (or clean workspace)
  • Gloves
  • Paper towels
  • Micropore surgical tape (the medical tape you’d get from any store)
  • 70% isopropyl alcohol
  • Sharp scissors
  • A lighter or spirit burner (kept outside the still air box if using, to reduce fire risk)
  • 10 ml spore (or liquid culture) syringe

For spawning to bulk:

  • Monotubs (a 4-quart tub holds 1 to 2 bags)
  • Pasteurised bulk substrate (e.g. coir-vermiculite-gypsum mix)

We recommend 10 bags because you should not use more than 1 ml of spore solution per bag. Using too much spore solution can lead to excessive moisture in the substrate, which can lead to contamination and rot.

READ: How to Lemon Tek: A Complete Guide for Mushroom People

A Step-by-Step Guide to Spiderman Tek

You can use a still air box to do your inoculation if you have one, or you can create a still air room in your bathroom or a small walk-in closet. Put any pets out of the room, clear the space, close windows and doors, wash your hands (or wear latex gloves), wipe down all surfaces with 70% rubbing alcohol, and work as quickly as possible. 

  1. Gather all your supplies; in a tek like this, working quickly and neatly is essential.
  2. Wipe down your hands and the outside of the rice bags with the isopropyl alcohol.
    Image of Rubbing Uncle Ben Bag with Cloth
  3. Do the same with your scissors and syringe, allowing the alcohol to evaporate before you start work.
  4. Massage your bags! Break up the rice so it’s not a solid mass.
  5. Being very careful and keeping the needle guard on, shake up your spore syringe to evenly distribute the spores.
  6. Remove the needle guard and set it aside.
  7. Flame sterilize your needle. It should glow red for several seconds.
    Image of Syringe being Lit with Lighter
  8. Snip the corner of the bag and quickly grab your spore syringe.
    Image of Cutting Corner of Uncle Ben Bag
  9. Inject 1 ml of spore solution into the bag. Don’t inject into the rice, just let the solution go on top of it.
    Image of Syringe Inserted into Uncle Ben Bag
  10. Use micropore tape to tape over the hole while it’s open; the easiest way to do this is to do one bit of tape over the top and one around the side, making sure the two pieces meet.
  11. Write the date of inoculation and the species of mushroom on the outside of the bag with a Sharpie. Repeat for all your bags.

There is an optimum temperature for your inoculated rice bags to sit in, and it’s between 70 F and 80 F (21 C and 27 C)—about the normal temperature you’d have your thermostat set at, or normal late spring/early summer conditions in North America.

When the entire bag feels solid and when your cursory glances inside the clear portions of the bag show that all the rice has become one big white block of mycelium, your Spiderman Tek is ready to be taken to the next level.

Once your bags are fully colonized, simply break them up and mix them into your prepared bulk substrate. Most new growers use a 1:1 to 1:4 rice to bulk substrate ratio by volume, which helps avoid contamination and ensures quick colonization times. However, if you’re really trying to stretch out your mycelium you could go up to 1 part rice to 10 parts bulk substrate—just be aware that your chances of contamination are higher at these ratios.

Issues You May Run Into

Keep an eye on growth through the clear window in the bottom of your rice bags, and gauge how they’re doing by feeling the bags to see if they’re solidifying. Ideally you don’t want to be handling them a lot—they aren’t airtight and the more handling you do, the greater the risk of exposing them to contaminants.


It’s normal to see a little moisture at the bottom of your rice bag, and this might even have a slightly orange tint; this is what’s known as “pee” or metabolites, and it’s nothing to worry about. What is of concern is anything that looks or smells like mold, rot, or another contamination. The rice shouldn’t be too wet or mushy (think risotto or wetter), and the growth should be a nice strong white growth rather than anything fuzzy or yellowish/greenish. If you do suspect that there’s something nefarious happening in one or more bags, separate these from the rest of the batch and keep them in a different place to stop the contamination spreading to the rest of the bags through the air. Once you see the visible signs of mold in a bag, the spores will already have moved through the inside of the mycelial block. If there’s mold, toss and try again. Thankfully, these bags are cheap.

You may notice navy blue patches on your mycelium block when you bring it out of the bag. A lot of first-time growers mistake these for contamination and freak out, but it’s most likely just “bruising” from where you’ve been handling the bags. 

Not Colonizing

If you’re growing “out of season,” it’s easy enough to keep your growing area warmer by applying a cheap heating pad bought online. Note that if your place is colder than optimum, it will just take longer for the bags to colonize—but if it’s too warm, you risk overheating the bags and killing off the mycelium, ultimately welcoming contamination in. We would tend towards lower temperatures with no heating pads, but if you do use them, keep the bags elevated so they’re not sitting directly on the heat mats as this can “cook” the rice at the bottom of the bags and cause rot or introduce contamination, neither of which you want. 

This article is an extract from the expanded and updated second edition of best-selling The Psilocybin Mushroom Bible by Dr K Mandrake and Virginia Haze, forthcoming from Green Candy Press in May. 

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DoubleBlind is a trusted resource for news, evidence-based education, and reporting on psychedelics. We work with leading medical professionals, scientific researchers, journalists, mycologists, indigenous stewards, and cultural pioneers. Read about our editorial policy and fact-checking process here.

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DoubleBlind Magazine does not encourage or condone any illegal activities, including but not limited to the use of illegal substances. We do not provide mental health, clinical, or medical services. We are not a substitute for medical, psychological, or psychiatric diagnosis, treatment, or advice. If you are in a crisis or if you or any other person may be in danger or experiencing a mental health emergency, immediately call 911 or your local emergency resources. If you are considering suicide, please call 988 to connect with the National Suicide Prevention Lifeline.

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