Do You Need Distilled Water for Misting Mushrooms?
If you’re new to growing mushrooms, you might be wondering whether you must use distilled water to mist your mushroom kit or soak (dunk) your substrate. The short answer: no, you don’t need distilled water for misting or dunking after your mushrooms have colonized. Clean, fresh tap water works great!
In this post, we’ll explain why tap water is usually the best choice for fruiting mushrooms and how RyzaPods – our easy, self-contained grow kits – make the process simple and worry-free. We’ll also clarify when sterile conditions do matter (during early stages like inoculation and colonization) and when you can relax and use water straight from the tap.
At Ryza, we want to make your life easier, so here’s a summary of the points of this post:
Distilled water is NOT necessary for misting or dunking mushroom substrates after colonization.
Clean, fresh tap water works perfectly well for misting and dunking mushrooms in the fruiting stage.
RyzaPods simplify mushroom cultivation and are designed to be used easily with regular tap water.
Tap water often contains beneficial trace minerals and tiny amounts of chlorine that help protect against contamination at fruiting.
Avoid stagnant or old water - use fresh tap water to maintain a healthy growing environment. Don’t let water sit for more than a day or two in your spray bottle. Allow your spray bottle to completely dry when not being used so microorganisms don’t grow inside the spray mechanism.
Distilled or sterile water is primarily useful in inoculants and if needed, during colonization stages - not fruiting.
Save time, money, and hassle by confidently using tap water when misting and dunking your mushrooms.
Can You Mist Mushrooms with Tap Water?
Yes – you can absolutely mist your mushrooms with tap water. We’ve cultivated mushrooms in hundreds of RyzaPods, and we always use clean, fresh tap water to mist and dunk our mushrooms. In fact, most home cultivators use fresh, plain tap water to keep their mushroom habitat humid. Once your substrate is fully colonized (covered in white mycelium), the risk of contamination from tap water is very low. The mycelium has established itself and is quite resilient at this fruiting stage. A few stray microbes in potable tap water won’t easily disturb it. As one experienced grower put it, if the water is clean enough for you to drink, it’s clean enough for your mushrooms.
When you begin fruiting (for example, when you remove the lid of a RyzaPod and start misting the substrate and humidity dome), using water straight from the faucet is both convenient and effective. Fresh tap water contains a tiny amount of chlorine (in treated municipal water) that is intended to kill harmful microbes. This trace chlorine won’t hurt healthy mushroom mycelium – if anything, it can help inhibit unwanted bacteria or mold. Many growers find that misting with tap water yields excellent pinning and fruiting, with no increase in contamination. Just be sure the water is fresh (not old or stagnant). For instance, don’t use water that’s been sitting in a bucket or spray bottle for weeks, as it could have built up bacteria. It’s best to refill your misting bottle with clean water regularly (every day or two) so you’re always spraying with fresh, clean tap water.
Pro tip: If your tap water has a strong chlorine smell or you’re concerned about it, you can fill a clean pitcher and let it sit uncovered for 12-24 hours. This allows chlorine to dissipate. (Some cultivators also boil the water and let it cool as an extra step, but this isn’t usually necessary.) In most cases, you can use it straight from the tap without any special treatment. The key is that the water is potable and not contaminated. Well water, spring water, or filtered water can also be used for misting, but there’s generally no need to go out and buy bottled or distilled water for your mushrooms.
When misting, spray the water lightly over the substrate surface and the sides of your fruiting chamber or humidity dome. You want to create a fine mist that keeps the environment humid (around 90+% humidity) without making pools of water. The mushrooms love humidity – it mimics the damp morning air of their natural habitat. Misting with tap water a few times a day (or as needed to maintain moisture) is usually enough to keep them happy. You’ll likely notice small water droplets on the mycelium or developing pins; that’s normal and beneficial. Just avoid over-saturating to the point of waterlogged substrate. With a kit like RyzaPod, the included humidity dome helps retain moisture, so you only need to mist to replenish what evaporates.
Bottom line: You can mist your mushrooms with tap water confidently once they’re in the fruiting stage. It’s easy, safe, and what most growers do. Save yourself the hassle and expense of distilled water – your mushrooms will do just fine with the clean water coming out of your faucet.
Is Distilled Water Better for Mushrooms?
It’s a common misconception that you should use distilled water for mushroom growing. In reality, distilled water is not better for misting or dunking mushrooms in a home grow setup. While distilled water is very pure (it contains no minerals, chlorine, or microorganisms), those qualities don’t provide any special benefit to mushrooms at the fruiting stage. In fact, using only distilled water can introduce a few downsides:
No Mineral Content: Mushrooms, like all living things, use trace minerals. Tap water typically has small amounts of minerals (like calcium, magnesium, etc.) that pose no harm and might even be beneficial to your mycelium. Distilled water has had all minerals removed. There’s anecdotal evidence among cultivators that using strictly distilled water can cause the mycelium to leach minerals out of the substrate or its own cells (because the pure water can draw out nutrients in an attempt to reach equilibrium). While your mushrooms won’t immediately shrivel from a bit of distilled water, they don’t gain anything from its purity. Using tap water provides a more natural balance for the mushrooms.
Lack of Sanitizing Agents: As mentioned, tap water often contains a minuscule amount of chlorine or other treatment agents that keep bacteria at bay. Distilled water is sterile at first, but once exposed to air it can actually be a great blank slate for contaminants to land in – there’s no chlorine to suppress them. With a fully colonized substrate, contamination risk is low regardless of water type, but tap water’s trace chlorine offers a tiny extra guard. Distilled water offers no such protection once it’s out of its bottle. In practice this difference is small, but it’s something to consider: regular water isn’t actually “dirtier” for your grow at fruiting stage.
Extra Effort and Cost: Distilled water isn’t necessary for mushrooms, which means buying and using it is an unnecessary step. Mushroom growing is fun but can get over-complicated by myths. Realistically, you’ll get the same (or better) results using tap water for misting as you would with distilled. By skipping distilled water, you save yourself a trip to the store and a few dollars. More importantly, you avoid the false sense that you must maintain laboratory conditions at all times – you don’t, once you’re fruiting. Mushrooms fruit in nature under rain and tap-like water conditions, not ultra-pure water. So you’re actually emulating nature more closely by using normal water.
They “Contaminate Easier” with Distilled: Many veteran growers explicitly advise against distilled water for fruiting. For example, it’s been noted that mushroom cakes or substrates tend to get contaminated more easily if you use distilled water exclusively. This could be due to the reasons above (lack of chlorine, stress on mycelium, etc.). While every grow is different, the consensus in the mushroom community is that distilled water offers no advantage for misting or dunking – and might even be a slight step backward. Tap water is tried-and-true.
In summary, distilled water is not better for mushrooms in the fruiting stage. It’s an unnecessary precaution that mushroom growers have learned to let go of. Good results are consistently achieved with plain tap water. If you already have distilled water on hand and want to use it, it likely won’t harm anything – but you should know it’s not required at all. You can mix it with tap water or add a pinch of salt/minerals if you’re worried about purity, but again, those extra steps aren’t usually needed for a successful grow.
(Side note: Distilled or sterile water does have its place in mushroom cultivation before fruiting. For instance, making spore syringes or hydrating grain spawn in lab settings might require sterile water. Some advanced cultivators store mushroom cultures in distilled water for long term preservation. However, those are specialized tasks outside of normal home grow routines. When it comes to misting your grow kit or dunking a cake, you can put the sterile water aside and use the tap.
What Kind of Water Should You Use for Mushroom Growing?
For the fruiting stage of mushroom growing (when you’re misting and soaking the colonized substrate), the best water to use is clean tap water straight from the tap. To recap and clarify: distilled water is not required for misting or dunking. In fact, many growers prefer non-distilled water for the reasons we discussed. Here’s a quick guide to water use at different stages of cultivation:
Inoculation & Colonization (Early Stages): This is when you do need sterile conditions. You’ll typically inject spores or liquid culture using a sterile syringe into a sealed, pre-sterilized substrate (like the rye berry and coir mix inside a RyzaPod). During this stage, you do not add water or expose the grow to the open air at all. Everything stays sealed up, warm, and clean while the mycelium colonizes the substrate. Because it’s a closed environment, you don’t have to worry about misting yet. Just make sure you followed proper sterile technique when inoculating (e.g. sanitize the injection port, use clean hands/gloves, etc.). The moisture needed for colonization is already in the substrate from when it was prepared. (If you’re making your own substrate or grain jars at home, you’d typically use tap water to hydrate them before sterilization. After sterilizing in a pressure cooker, that water is sterile within the substrate. So either way, early on everything is handled in a sanitary way.)
Fruiting Stage (After Full Colonization): Once the substrate is fully colonized (completely white with mycelium) and you move to fruiting conditions (introducing fresh air, light, and humidity), sterile conditions are less critical. Now is when you’ll start misting the substrate with water to keep humidity high, and possibly dunking the substrate between flushes to rehydrate it. At this stage, you should use plain tap water (or any potable water). There is no need to sterilize the water used for misting or soaking. In fact, opening the container to fruit means you’re already exposing it to the normal environment. Your best defense against contamination is the fully colonized mycelium, which is quite strong and occupies the food source so invaders have a hard time taking hold. Using clean water helps keep the surface humid and the mushrooms hydrated – it does not introduce contamination in any significant way. Just avoid using water that might contain obvious dirt or germs (for example, don’t reuse dirty dish water or something silly like that – stick to drinking water quality from the tap).
Misting Your Mushrooms: Use a clean spray bottle filled with tap water. Aim a fine mist above the growing mushrooms and across the inner walls of any humidity dome or fruiting chamber. Misting both the substrate and the chamber walls maintains a humid micro-climate which mushrooms need for development. Do this a few times per day or as needed to keep the environment damp (but not waterlogged). Tip: If your spray bottle has been sitting, rinse it out and refill it with fresh water regularly. Do not add peroxide or any other additives to your misting water; plain water is best. Mushrooms don’t need fancy supplements in their spray – they get all nutrients from the substrate, the water is just for humidity.
Dunking (Soaking) the Substrate: After you harvest a batch of mushrooms (a “flush”), the cake or substrate block will be thirsty. Dunking is the process of replenishing its moisture for another flush. To dunk, you simply fill the container with water until the substrate is submerged. Again, use clean tap water for this. Let it soak for a few hours (some growers do 2-4 hours, others up to 12 hours for thick substrates – with kits like RyzaPods, even a 1-2 hour soak can work well because the substrate isn’t huge). After soaking, gently pour out the excess water and put the lid or humidity dome back on. Then resume normal misting and fruiting conditions. This dunk gives the mycelium a fresh drink and often leads to a robust second flush. You do not need distilled or sterile water for dunking – the substrate is fully colonized and can handle tap water without issues. Just make sure the container you’re dunking in is reasonably clean (if you’re using the RyzaPod tub itself, it obviously is clean from the grow; if you transfer a cake to a separate dunk tub, ensure that tub is clean). Using room temperature or cool tap water is fine; extremely cold water isn’t necessary unless you are intentionally cold-shocking a specific species (mostly not needed for common edible varieties).
So, what water is best for mushroom growing? For all post-colonization steps (misting, humidity control, and soaking), use fresh, drinkable tap water. If your tap water is questionable or has known contaminants (very rare in developed areas, but if you wouldn’t drink it, don’t use it), then use filtered or bottled water. There’s generally no advantage to using distilled water for growing mushrooms in a home setup – tap water is the go-to choice. Save distilled water for tasks that explicitly require sterility or mineral-free water (which are few and far between in basic mushroom cultivation). In summary: Clean tap water keeps things simple and yields great results in mushroom cultivation.
Quick Tips for Water and Mushroom Fruiting
DO use fresh tap water to mist and dunk after colonization. It’s convenient and works well.
DON’T use old or stagnant water. Empty and refill your misting bottle often. If water sits around exposed to air for days, dump it and get fresh.
DO keep early stages sterile. Remember that all the sterile technique precautions are critical before and during colonization, not during fruiting. By the time you’re using tap water, your substrate should be fully colonized and in a fruiting container/dome.
DON’T waste money on distilled water for spraying mushrooms. Put those funds toward another grow kit or different mushroom varieties to grow!
DO observe your mushrooms and environment. If you ever notice odd colors like green or black (signs of contamination), it’s usually an issue from earlier or from severe airborne exposure – not your tap water. A healthy white mycelium will generally fend off intruders during fruiting. Keep your growing area clean and well-ventilated, and you’ll be in good shape.
RyzaPods Simplify Your Mushroom Growing (No Distilled Water Needed!)
One of the big benefits of using RyzaPods – our all-in-one, self-contained grow system – is that they take the guesswork out of decisions like “what water should I use?”. We designed RyzaPods to be beginner-friendly and forgiving, while still delivering great results for experienced growers. When you use a RyzaPod kit, you get pre-sterilized nutritious substrate sealed in a container with an included humidity dome. All you need to do is inoculate with your spore or liquid culture syringe (following the provided sterile instructions), and then let it colonize. By the time you’re ready to fruit, the hard part is over! The substrate will be fully colonized, and the pod itself serves as the fruiting chamber.
Here’s how growing with RyzaPods makes things easier for you:
No Need for Lab Conditions: RyzaPods arrive already pasteurized/sterilized and sealed. During colonization, you keep them closed – no exposure to outside air or water. This means contamination risk is extremely low. When it’s time to fruit, you simply pop off the lid and attach the humidity dome. At that point, it’s totally fine to start misting with regular tap water. The kit’s design (with a clear dome and filter vents for airflow) maintains a clean micro-environment. You don’t have to maintain a separate sterilized fruiting chamber or worry about introducing germs with each spray. The self-contained system has you covered.
Humidity Dome = Less Misting Worries: Each RyzaPod comes with a dedicated humidity dome that fits perfectly on the pod. This dome keeps moisture and humidity around your substrate, reducing how often you need to mist. When you do mist, you’re spraying into an enclosed space that’s shielding your grow from large airborne contaminants. This means you can mist freely with tap water and trust that the combination of the dome and the robust mycelium will prevent issues. The dome has a filter patch that allows fresh air exchange (FAE) without letting dust or spores just fall directly inside. In short, the RyzaPod setup creates an ideal balance of humidity and cleanliness, making tap-water misting a non-issue.
Empowering for Beginners: We know that starting out, many growers feel they have to be ultra-cautious about every little thing – water included. RyzaPods are built to empower you to grow mushrooms with confidence and minimal fuss. There’s no need to sterilize water, fan fruiting chambers, or construct complex terrariums. If you can operate a spray bottle and follow a simple schedule, you can provide the perfect environment for your mushrooms. Using just straight tap water, our growers have consistently harvested beautiful flushes of mushrooms from their RyzaPods. By simplifying decisions like water type (just use what you have!), RyzaPods let you focus on the fun part – watching your mushrooms grow – rather than getting bogged down in unnecessary steps.
Great Results with Simple Ingredients: Our team at Ryza has tested and refined these kits to ensure that using everyday resources yields success. We’ve had growers ask “Do I need to mist with distilled water or boiled water?” and we’re happy to tell them “Nope! Good old tap water works.” The proof is in the harvest: kits misted with tap water produce flush after flush of healthy mushrooms. By not overcomplicating the process, you actually set yourself up for better outcomes. Mushroom cultivation doesn’t have to be intimidating, and with the right kit, even tasks like watering are straightforward.
Finally, it’s worth reiterating: once your substrate is colonized, contamination risk is minimal provided you use common sense. Keep your tools (like spray bottles) clean, use fresh tap water, and handle your grow in a reasonably clean area, typically on a counter or table, away from excessive dust or pet dander. There’s no magic in distilled water that will make mushrooms grow better. In fact, many successful grows have shown that tap water is ideal for misting and soaking. So you can put that distilled water aside and save it for another purpose.
In conclusion, if you’re fruiting mushrooms (whether in a RyzaPod or any other fruiting chamber), feel free to use clean, fresh tap water for all your misting and dunking needs. You’ll avoid unnecessary effort and your mushrooms will thrive just the same. Sterile technique is crucial at the start (think inoculation and incubation), but when it comes to keeping your mushrooms hydrated and happy, you can rely on the convenience of the tap.
Happy growing, and may your mushroom journey be bountiful! If you’re using RyzaPods, rest assured that we’ve set you up for success – just follow the steps and enjoy watching nature do its thing. And if you haven’t tried RyzaPods yet, check out our RyzaPod grow kits to get started with an easy, no-fuss mushroom cultivation experience. Remember: you do not really need distilled water for misting mushrooms – simple tap water and a simple grow kit are all you need to grow mushrooms like a pro.
