Growing Mushrooms from Kits (Comprehensive Guide)
Updated: May 4
One of the easiest ways to dip your toe into the world of mushroom cultivation is to start with a ready-made mushroom grow kit. Grow kits provide a quick and easy yield, without the need to invest in additional equipment or to go through the rigmarole of making your own grow blocks from scratch, which can be time consuming and potentially prone to failure if good process is not followed.
Grow kits provide the opportunity to watch mushrooms grow, and harvest and eat them, as well as getting a feel for what it's like to grow mushrooms and what kind of growing conditions they thrive in. In this post we will answer some common questions that people have about mushroom grow kits and share some tips and advice for a successful harvest! If you see any terms here that you are unfamiliar with please feel free to check out our glossary of mushroom cultivation terminology.
WHAT IS A MUSHROOM GROW KIT?
A mushroom grow kit is basically exactly the same as a commercial mushroom production block that would be used in mushroom farms, but just a singular unit that you can grow and enjoy at home. They are made from substrate (organic materials that mushrooms eat such as sawdust, seed hulls, straw, woodchips) which has been hydrated and sterilised (usually by steaming). The substrate is usually held within a specialised mushroom growing bag. After it has cooled, the substrate is inoculated with grain spawn containing the mushroom culture of the desired species.
The growing block is incubated for a week or two until the mushroom mycelium (a fibrous white material) has spread through all of the substrate. This process is called colonisation. Once the substrate is fully colonised then the grow kits is ready to send to the customer.
From here all that you need to do is follow the instructions that come with the kit. This will basically be to provide adequate growing conditions for the grow kit, which usually includes keeping it in a humid but well aerated space out of sun and wind, and lightly misting with a spritzer bottle once or twice a day. Then you can watch your mushrooms grow, harvest them when they are ready and enjoy them in a delicious meal!
It should be noted that mushroom grow kits are living organisms and need to be opened up and put into fruiting conditions as soon as you get them. You can't tuck it away to grow on a rainy day some time in a couple of months, as the organism would likely have spoilt by then. If you want to buy a grow kit for someone as a gift or require it at a specific time, you can feel free to order in advance and use the 'add a note' feature in the online checkout process to tell us what date you want it delivered by. Or alternatively you can purchase a digital gift certificate for the value of a grow kit which the recipient can redeem any time they like (no expiry date)!
WHAT TYPES OF MUSHROOMS ARE AVAILABLE AS GROW KITS?
Here in Aotearoa New Zealand, the types of mushrooms that can be grown are partially limited by what species are allowed here under our strict biosecurity rules (which are in place to protect ecosystems and primary industry from unwanted pests and disease). As such, most cultivated mushrooms here will be either from the list of allowed imports, or native species. Here at MycoLogic we celebrate indigenous fungi and have many unique strains of native mushrooms which we also offer as grow kits for you to enjoy at home. Our core range of grow kits include Native Oyster Mushroom, Pekepeke-kiore ('NZ Lion's Mane') and Turkey Tail. We also on occasion release kits of other mushrooms for people who are interested in trying something different, depending on the season and what will grow well at that time.
HOW DO I LOOK AFTER A MUSHROOM GROW KIT?
If you purchase a grow kit from MycoLogic, it will come with full printed instructions which are specific to each mushroom species. But some general principles apply to all mushroom grow kits. I find that it helps to imagine the kind of environment where you might see lots of mushrooms growing on a walk in the bush, which is usually somewhere that is humid and shaded but also fresh and airy.
Most new growers tend to over estimate the amount of humidity that mushrooms need, and under estimate the amount of fresh air exchange they need. Mushrooms love fresh air! And if they are in a spot with mild temperatures, and out of the wind and direct sunlight, they will not generally need too much misting. The trick with misting is to try to create humidity around the general area that the mushrooms are growing in, without saturating the mushrooms themselves. Excess water on the surface of mushrooms can stunt their growth and make them water logged which can lead to rot and contamination.
Shaded, well ventilated areas which are protected from wind and sun are great spots to grow mushrooms. This could be in a garden shed, in a greenhouse underneath big plants like tomatoes, under a deck or alcove, in the laundry room, and so on. Indoor living areas like kitchens, bathrooms or bedrooms are not generally great places to grow mushrooms, because homes are (ideally) warm and dry which isn't what mushrooms want! Also, when mature mushrooms begin to release spores it's better for this to not be in your living space. You can check out our fruiting environments grow guide for more detailed information about creating a great microclimate for mushroom growing, and if you want a super easy and effective solution to a perfect grow kit arrangement, check out our mini mushroom grow tents.
HOW DO I GET EXTRA CROPS (FLUSHES) FROM A MUSHROOM GROW KIT?
A fruiting block will usually not have used up all of its resources after just one crop / flush of mushrooms. If well cared for, mushroom grow kits are capable of producing two, three or more crops of mushrooms before they are fully 'spent'.
After the first crop of mushrooms have been harvested, there are several steps to follow to help the block produce another flush. The first step is to make sure that you have cleared away any remaining stem material, so that only substrate remains in the hole. Remnant stem material can be an invitation for pests or contamination to take hold.
After this, the mycelium will want to go through a natural resting phase of about a week. During this time, you don't need to do a whole bunch - just keep the kit in the same environment that it was in for fruiting and continue to protect it from gnat invasions.
After about a week, if you don't already see the next generation of mushroom pins forming, you can increase the humidity for a few days, which can be a great way to trigger the onset of a new flush. This can be done by increased misting each day, or leaving a tray of damp perlite, pumice or pebbles right next to the grow block. If the substrate seems dry, you can try spritzing a few sprays of water directly onto the substrate through the holes where the mushrooms grew, to rehydrate the substrate and create localised humidity right where the pins (baby mushrooms) are going to form.
From here, its just a waiting game, keep maintaining good fruiting conditions and eventually the next crop of mushrooms will grow! This can take anywhere from one to three weeks depending on the species of mushroom and the temperatures and humidity of the grow space.
ARE MUSHROOM GROW KITS WORTH IT IN TERMS OF COST vs YIELD?
All MycoLogic mushroom grow kits, if well cared for, should easily return more than the cost of the kit in the dollar value of mushrooms, compared to the retail price of fresh or medicinal mushrooms. For example, our native phoenix oyster mushroom kits typically yield in excess of 1kg of oyster mushrooms across two or three flushes. Oyster mushrooms generally retail for $50 to $80 per kg at markets or in shops, so not only do you get more than the cost of the kit in mushrooms, you also get to enjoy watching them grow, pick them at the perfect moment and take them straight into the kitchen to prepare a meal, that's unbeatable freshness! Our pekepeke-kiore / NZ Lion's Mane kits typically yield well in excess of 500g of mushrooms across two or three flushes, these mushrooms are not commonly available for retail sale but when they are they normally sell for at least $80/kg. For Turkey Tail kits, the amount of mushrooms yielded would be the equivalent of a decent jar of capsules that would have a value of at least $60. So, long story short, yes, mushroom grow kits are very much 'worth it' if you look after them well according to the instructions and make the most of your home grown produce!
WHAT CAN GO WRONG WITH MUSHROOM GROW KITS?
One of the benefits of buying a ready-to-fruit mushroom kit is that lots of the hard work has been done, and the most difficult parts of the growing process have already been completed in a laboratory environment. All MycoLogic grow kits are run through a quality control inspection prior to dispatch to ensure that they are in top condition
when sent. But, like most things in life, especially when dealing with living organisms, mushroom grow kits are not entirely fool proof! So here are some of the potential issues you can run into when growing mushrooms and how to identify them
Fungus Gnats. These are the #1 enemy of the mushroom cultivator! Fungus gnats (also known as Sciarid flies or Phorid flies) are small winged insects that love mushrooms, they can detect the smell of fungus from quite a distance and will hone in on mushrooms and mycelium in order to lay their larvae, who will tunnel through the material while they eat it. Needless to say, fungus gnats are not ideal, and can quickly ruin an otherwise perfectly good crop of mushrooms. There are two main kinds of fungus gnats in New Zealand - small black ones that look very similar to sandflies, and slightly larger ones which look very similar to mosquitoes (e.g. visible legs and wings and a longer abdomen). Both kinds are bad, but the ones that look like mosquitoes are the worst as they are larger and more destructive. When it comes to fungus gnats, prevention is better than the cure. In other words, it's well worth it to do what you can to prevent a gnat infestation in the first place. Physical exclusion of gnats, to stop them getting to your mushrooms in the first place, is a great option. Growing mushrooms within a space where any openings or gaps are protected by a fine mesh works pretty well. Our mini mushroom grow tents are fully gnat proof! In addition to trying to keep gnats away from your mushrooms entirely, some other contingency plans can e put in place as well. Hanging a yellow sticky card or two in your grow area can be very effective at picking up any rogue gnats before they explode in population. Mushroom growers have been known to employ a range of other creative solutions as part of a multi-pronged attack for fungus gnat prevention and control, such as electronic bug zappers, beer/wine or vinegar traps, carnivorous plants or even allowing spiders or praying mantis to inhabit the grow space to actively patrol the area for invaders! If gnats have become established in a grow block, its a good idea to put it outside and definitely move it away from other mushroom grow blocks so that the gnats don't spread into those.
Not enough fresh air. As mentioned previously, mushrooms 'inhale' oxygen and 'exhale' CO2, the same as us humans. If mushrooms are growing in too enclosed of a space, the CO2 that they exhale can start to accumulate and affect the mushroom growth. The main symptom of high CO2 levels is spindly, elongated growth. If you notice that your mushrooms are looking a bit 'stretched out' or not as dense and robust as you'd expect, they probably need more fresh air. Move them to an airier spot or increase the ventilation in their existing environment.
Environment too wet or too dry. When tending to a mushroom grow kit the goal is to maintain a moderately humid but fresh environment around the mushrooms that are growing, but without saturating the mushrooms themselves so that they become waterlogged, which is not good. You can usually tell by observing the mushrooms themselves whether its too wet or too dry - mushrooms that don't have enough humidity will start to turn yellow, brown or orange at the edges and cracks may appear on the edges or tops of the caps. Mushrooms that are too wet will look soggy, or be glistening or have beads of water in them. Adjust the conditions accordingly.
Contamination. Mushroom growing substrates are made especially for growing fungus... the goal of this is to grow the kind of fungus that we want (mushroom mycelium), but on occasion this delicious substrate can get invaded by other unwanted fungi such as molds. Molds can show up as patches of green, grey, black, white, red, orange or yellow colouration on the surface of the substrate. Green mold is the most common which is of the Trichoderma or Penicillium persuasion. If the contamination is only tiny, under the size of a 50c piece, the mushroom mycelium can often overpower the contaminant and continue to grow perfectly well. But if contamination is widespread in a grow block then it is best to remove this block from the growing environment and use the substrate as mulch or in a compost heap or worm farm. All MycoLogic grow kits are prepared in a sanitary laboratory environment and as such our incidents of contamination are very very low. We also do a thorough quality control inspection of kits and other products prior to dispatch to ensure that they are free of contamination. But if in the unlikely event you notice some contamination on a grow kit that you have bought from us, simply email us with a photo of the problem and we will be more than happy to help you out and, if needed, provide a replacement kit free of charge - too easy!
Mushrooms are overmature. It's important to pick your mushrooms at the right time. Mushrooms that are left to grow past prime picking stage can become overmature, which means that they begin to release a lot of spores (messy!), degrade in quality, texture and flavour, and begin to sap a disproportionate amount of moisture and nutrients from the grow block, robbing resources from potential subsequent flushes. So, it's best to try to pick mushrooms at the optimal harvest time. This is especially important for fast growing mushrooms like oyster, shiitake, enoki or tawaka, all of which can go from 'good to pick' to 'over mature' in just a day or two! For these species it's best to keep a good eye on their progress, and when the caps start to open or flatten out, it's time to pick! Slower growing mushrooms like Pekepeke-kiore (NZ lion's mane) or turkey tail, have a wider 'window of opportunity' for harvesting and are generally picked when the growth of the fruitbody starts to slow down after an initial stage of more rapid growth.
Too hot or too cold. Generally speaking, mycelium and mushrooms grow faster when it is warm and slower when it is cold. But extremes at either end of the spectrum can be damaging to the mushrooms. As long as it's above freezing, cold temperatures will not usually kill most species of mushrooms especially not native ones which have evolved here in New Zealand. But in winter time in cool spaces, mushroom growth can be incredibly slow. The upside of this is that cold-grown mushrooms are usually of exceptional quality with great texture and depth of flavour, and the other bonus is that there doesn't tend to be any gnats around in the winter time. So if you've got the patience for it then there's absolutely nothing wrong with growing mushrooms in cool seasons. Most of the mushrooms that MycoLogic supplies as kits or cultures are the happiest fruiting between about 12 to 24°C. When the temperature is very warm, mushrooms are more susceptible to drying out as well as to pests and contamination. The mushrooms can also grow very quickly, which can compromise their taste and texture and make them become over-mature (and releasing spores) sooner. Temperatures above 30°C should be avoided if possible.
The issues listed above are the most commonly encountered challenges for the hobbyist mushroom cultivator. But with a bit of practice and diligence, all of these issues can be fairly easily avoided. If you are growing a MycoLogic grow kit and have any questions, you can feel free to contact us with photos and a description of what's going on. The Mushroom Cultivation New Zealand facebook group is also a good, active community of mushroom growers in New Zealand with many members who are happy to share tips and advice and answer questions!