It may seem like a lot of work, but so is starting plants from seed! I'd rather put in a few minutes of cleaning in the beginning to ensure happy, healthy seedlings later on!
MARSHINE supply professional and honest service.
Now your seed trays are clean and sanitized, and ready for a new crop of seedlings! I'll repeat the same disinfecting process for any plastic pots I use later on when my plants get too big for their tray, but the weather isn't warm enough for them to go outside yet.
After each seed tray has been thoroughly rinsed, allow them to air dry. I just pop mine in a plastic bin at an angle so they can drip dry on the kitchen counter. But if your weather is nice, you can leave them outside to dry in the sun.
You could also mix up a 10:1 ratio of hydrogen peroxide and water in a spray bottle and mist it over your seed trays. This works best if you have a lot of trays to disinfect because you can do it outside, then hose them all off.
I fill my kitchen sink with warm water, then pour in about a cup of food safe hydrogen peroxide. Stack the seed trays so that they sit on top of each other instead of nesting together, so all the surfaces can soak properly.
Standard hydrogen peroxide (H202) contains chemicals that extends shelf life, but isn't great for plants. Instead, look for food safe hydrogen peroxide, which doesn't have anything added. Food safe hydrogen peroxide is approved for preventing and controlling microbes that can cause diseases in crops, and it breaks down naturally into hydrogen and oxygen in the environment.
I've seen some tutorials that recommend using bleach, but I don't want my kitchen smelling like a swimming pool! Plus, if you're growing edible plants in your trays, do you really want those chemicals in your food?
Now that your seed trays are clean, it's time to sterilize them. But what should you use?
This dislodges most of the dirt, but I'll usually add a squirt of Dawn dish soap to a bottle brush and swish it in each cell to clean out the rest. Make sure to rinse out the soap thoroughly!
Brush off any leaves or loose dirt, then give your seed trays a good rinse with a hose or the sprayer in your kitchen sink. Flip it over and spray through each hole to remove the gunk stuck to the bottom.
This post contains affiliate links for your convenience. Purchases made through these links may earn me a small commission at no additional cost to you.
I recently started growing lisianthus, yarrow, dianthus and snapdragons from seed in brand new trays, which don't need to be sanitized. But now it's eight weeks before my last frost date, and I have a huge stack of seed packets to plant, so it's time to clean and sanitize those old seed trays!
Before you start any seeds in a previously used tray, you need to disinfect it first! While some people say it's unnecessary, there's nothing more heartbreaking than discovering your seedlings have died unexpectedly from dampening off or other diseases. I'd rather be safe than sorry!
But when it comes time to start new seeds in late winter, all my trays are covered in gunk! They also could be harboring bacteria, fungus and viruses that could kill my new baby plants!
Spring is the busiest time in the garden, with seedlings to plant, containers to fill and weeds to pull. After I get my starts in the ground, I usually just stack all the trays on a shelf and forget about them until next year.
If you reuse seed starting trays from year to year, you need to disinfect them first! Here's how to clean and sanitize seed trays easily!
Last Updated on August 18,
One excellent way to reduce waste in the garden is to reuse your seedling containers and nursery pots! This applies to ones you intentionally purchased for starting seeds, or any containers you bring plants home in from the local garden center &#; which you hope to keep and use again. If we are going to reuse these things, properly sanitizing supplies and tools between use or seasons is an important step to keep your plants healthy and disease-free! This article will go over a few non-toxic methods used to sanitize garden supplies.
On this homestead, we use a variety of plastic nursery pots, 6-packs, and trays with dome lids for starting seeds. The supplies we choose are high quality, heavy-duty, and durable. They&#;re ones that are meant to be reused year after year without easily cracking and breaking! We choose these over the single-use products like peat pellets, though that is just our personal preference. Even if you use peat pellets, you most likely have trays or cells that they sit in. Those should be cleaned too. For more information on seed starting tips and best practices, check out this post!
While it may seem like just one more chore to do, and one that is easy to skip, sanitizing your garden tools and pots is something you should make an effort to do! Is sanitizing absolutely essential? Maybe not. Will all of your plants undoubtedly perish if you don&#;t do it? Probably not. On the other hand, starting the season with fresh clean supplies gives you a little extra (cheap!) insurance that your seedlings will be strong and healthy. It will also help eliminate that awful &#;what if&#;&#; or &#;I should have&#;&#; feeling if you do skip sanitizing, and something goes south.
When you are starting seeds and do not sanitize the seed containers, trays, and other pots between seasons, disease or fungal spores could be left behind and infect your new round of plants. This is especially a concern if you had any struggles with your seedlings the previous year. Or, if you are reusing containers from a garden center, potentially bringing in disease or pests that weren&#;t previously present in your garden.
One such disease that may inflict your new precious babes is called seedling blight, also known as damping off.
Damping off is a somewhat generic term for when seedlings just up and die on you. They&#;re chugging along, looking all cute, perky and spry, and then Bam! Dead. Done. It is so tragic and frustrating to experience!
One of the most obvious signs and symptoms is when the seedling stem gets super thin and weak just above the soil line, and then flops over or wilts. What happened? Most likely a soil-borne disease or fungus is at fault. Sanitizing can help prevent this, along with using fresh sterile bagged seedling mix when you start seeds &#; not soil from your yard! Re-using old soil is another way to introduce pathogens to new seedlings.
Damping off exemplified. See how thin and sad part of the stem got? There is no recovery form this. Photo courtesy of Marijuana Times
When you are out working in the garden, you should also take care to disinfect supplies &#; such as your trimming shears. This should be done periodically as a good habit, but should most definitely be done whenever you are working around a plant with a known and obvious disease, to prevent it from spreading. For example, after a trimming a plant that has powdery mildew, sanitize your tools (and wash your hands!) before moving on to other plants.
Before we get into the options of how to disinfect your supplies, I should note that it is important to try to start with fairly clean supplies at the beginning, before starting any of the methods below. I don&#;t mean clean clean. But at least lightly rinse or knock out any accumulated dirt before starting the disinfection process. The reason is this: the agent you use, be it vinegar or peroxide, will attempt to &#;clean&#; the dirt first, and use up a lot of its power and energy. So starting with less-than-filthy supplies will ensure your disinfectant is actually cleaning your pots and trays, not cleaning the dirt.
One way to kill off any bad guys is to sanitize your supplies with plain white vinegar. Most household vinegar is 5% in strength. If you are working with a small collection of trays and pots, this could very easily be done with a spray bottle full of undiluted vinegar. Spray everything down well, and let the vinegar sit to do its thang. To be effective, vinegar needs at least 10 minutes of contact time on the item. 20 minutes is even better. After that, wipe or rinse them off. You may not have to rinse them, but because it&#;s so acidic, I do. I worry about the vinegar breaking down the plastic and making it more brittle.
We reuse old cleaning bottles for vinegar spray, soap spray, or other homemade concoctions. Always clearly label your bottles!
We use this method to sanitize our garden shears, pots, or when working with a small number of seedling containers. I also spray down the interior walls of our greenhouse at least once a year. A spray bottle of vinegar is always readily accessible on this homestead! We actually use a homemade citrus and vinegar spray what we also clean our kitchen counters, sink, tub and shower with. Note: Due to its acidic nature, vinegar is not recommended for cleaning marble or granite countertops, and probably other types of sensitive stone. Do your homework before using it on yours! We just have crummy old laminate ones, for now.
If you want to learn more, please visit our website Sanitizing Seed Trays With Vinegar.
Well, when I was researching the various methods for sanitizing garden supplies, many sources said to use undiluted vinegar, or at least somewhere around 75% vinegar to water. When too diluted, vinegar doesn&#;t have quite the same oomph to disinfect. That means that if you are working with a decent amount of containers to sanitize, you&#;d need a fairly large amount of vinegar to fill a tub, soak, and effectively sanitize your supplies. The same contact time as spraying applies here too. If you have fewer supplies to clean at once, soaking them could work just fine!
Like vinegar, hydrogen peroxide is cheap, non-toxic, and effective at killing bacteria, viruses, mold, mildew, and fungus! Hydrogen peroxide is considered an environmentally-safe alternative to chlorine bleach. It breaks down into water and oxygen. Following the same steps as in option 1, fill a spray bottle with standard 3% household hydrogen peroxide (undiluted), spritz, and viola! Clean supplies. Also like vinegar, peroxide needs at least 10 minutes of contact time. Follow the same steps to wipe down or rinse off afterwards.
Basic 3% household hydrogen peroxide is a safe, non-toxic bleach alternative!
If you are going to stick with a spraying method for either vinegar or peroxide and have a lot of supplies to sanitize, it may be easiest on your hands and most efficient to use use a pump pressure sprayer that can put out a constant stream. You know, opposed to a normal spray bottle that you have to repetitively squeeze.
Disclaimer: To be honest, I have been putting off writing and posting this because I have a feeling this section may raise a lot of eyebrows, and a lot questions. I contemplated omitting this part completely. But for the sake of transparency and &#;real life&#;, I figured I better just go ahead and share how we cleaned our seedling containers this year. For the record, I am not saying option three is better than two or one! It was just what happened to work for us. If you aren&#;t comfortable with playing mad scientist, stick to option 1 or 2.
Read this section carefully. Do not ever mix straight undiluted hydrogen peroxide with straight undiluted vinegar. Especially in an enclosed container, like a spray bottle! Mixing these two creates an acid. It&#;s not quite as scary as it sounds though. It is only dangerous and unstable if you create a strong, undiluted solution and store it mixed in an enclosed container. Or if you work with it in strong quantities indoors and inhale it. Hear me out here though! I did my research.
About to make some homemade Peracetic Acid
By combining vinegar and hydrogen peroxide, they react to form peracetic acid. Peracetic acid is a highly effective sanitizer that is widely regarded as very environmentally safe. It was first registered by the US EPA as a disinfectant in . It is even more effective at killing microbes than bleach, and is used in place of bleach in the medical industry at times. Certain large chain grocery stories and restaurants use it as a sanitizer in their sink dispensers for cleaning dishes. Some cattle and beef industry facilities use it too! That&#;s pretty cool, if you ask me.
Yes it&#;s an acid, but so is vinegar. But you knew that though, right? Vinegars active ingredient, acetic acid, is actually a stronger acid than peracetic acid! If you correctly make a weak, diluted peracetic acid as I describe below, it is safe to work with.
If you google &#;Can you mix vinegar and hydrogen peroxide&#; the initial glaring answer you&#;ll come across is &#;NO!&#;. Again, that is mostly because of the concern of mixing it in an enclosed container. Warning bells also go off for some people when they see it makes peracetic acid. They&#;re like no, don&#;t create that stuff! Because at industrial strength, peracetic acid is highly corrosive, and a respiratory and skin irritant. It is made using industrial strength, highly-concentrated vinegar and similar hydrogen peroxide mixed together. While I appreciate people erring on the side of caution, that is not the household-level stuff we are talking about using here.
The reason we even went down this path was sort of by accident, and also by necessity. I certainly did not set out thinking, &#;Ooh, I wanna whip up a batch of homemade peracetic acid today!&#; It was more like: how can I get this task that I am not really looking forward to done as quickly as possible, with the supplies I have on hand? See, we had a TON of seedling containers to sanitize. We&#;re talking about one hundred 4&#; pots, several dozen 6-packs, and about a dozen trays and dome lids each. I absolutely did not feel like spreading them all out, spraying down each one on all sides, letting them sit, rinsing, and so forth. We also didn&#;t have nearly enough vinegar on hand in order to fill a large tub and soak everything at a high enough concentration to get the job done right.
I also really didn&#;t want to use bleach, so I started doing my homework. I saw options for peroxide, options for vinegar, options for bleach, and just one mention of mixing peroxide and vinegar to get a double-duty disinfectant. Unfortunately, that person didn&#;t include disclaimers about the hazards of mixing them undiluted, so I may reach out to them and bring that up. Reading their suggestion piqued my interest, but I definitely wanted to look more into this mixing business before doing it myself, since I know it&#;s very hazardous to mix some things &#; like vinegar and bleach for example.
I scoured the scientific community and academic journals for answers. I also read a lot of forums where people bantered back and forth about whether it was okay or not, like this one. People had all sorts of differing opinions, but I decided to listen most to the people who chimed in with &#;scientist&#;, &#;university research director&#;, and &#;chemist&#; next to their name. Because you know what they say about opinions&#;
This is the conclusion I came to: Household strength hydrogen peroxide (3%) and white vinegar (5%) can be used together safely (not mixed in an enclosed container!), especially if they are diluted and combined in sufficient water. The concentration of peracetic acid formed is so, so far below the industrial concentration that it will not be hazardous.
In a large clean plastic tub, about 15 gallons in size, I added just under two 5-gallon buckets full of water. They weren&#;t totally full because I had to carry and dump them, so it was probably about 7-8 gallons of water total. Then I poured in a full gallon of household white vinegar. Next, I added one 32 oz bottle of hydrogen peroxide. All good. Then I repeated the process with a second tub. Following this recipe, you could scale down to use a 5-gallon bucket mostly full of water (at least ¾ full), add about half a gallon of vinegar, and 16 oz of peroxide.
Round one soaking: the 4&#; pots we&#;ve been able to use over and over for years! Next up, the 6-packs. Then the trays and domes will get their bath last!
Next, I added as many pots or trays that would fit in and stay submerged. After they soaked for 15 to 20 minutes, I pulled them out and put the next batch in. Using a 5 gallon bucket nearby, I quickly dunked the now-sanitized pots and 6-packs into the bucket of clean water, to give them a rinse. For the larger trays, we gave them a quick spray with the hose. Then all the clean supplies went into the greenhouse to dry. For the extra dirty trays, I scrubbed them with a brush too. I had to do about 3 batches to get through everything while still giving them all adequate contact time. But it was way less of an effort than the other options, in my opinion!
Yep, I put my hands all up in it. Not a single tingle. It was fine. And I have fairly sensitive skin. Not that I would have done this job inside, regardless of what we were working with (too messy!)&#; but for the record, I did it all outside, so adequate ventilation was not a concern. Though I don&#;t really think it mattered. It didn&#;t smell like anything. Just a slight vinegar odor. From what I read, industrial strength peracetic acid is extremely strong and noxious. Like, it burns when you inhale it.
Dang! Look how dirty that cleaning solution was towards the end. We chose to start with the pots and 6-packs first, while the peracetic acid was still at its strongest, because those supplies are in most direct contact with the soil and seedling. The trays and dome lids were less of a priority, so they got the less fresh sanitizing solution.
I think so. And in this case, it was better than the alternative &#; either a very tedious task of spraying the supplies, using bleach, using uber-dilute peroxide or uber-dilute vinegar on their own, or not sanitizing at all! While I was scrubbing the trays, they bubbled a bit like peroxide does when it is working. I took that as a good sign!
After all was said and done, I came across this quote by a food scientist at Virginia Polytech that made me feel even more assured that my little science experiment went pretty well:
&#;If the acetic acid [vinegar] got rid of 100 organisms, the hydrogen peroxide would get rid of 10,000, and the two together would get rid of 100,000 organisms.&#;
Susan Sumner, Science News Online
So even though my vinegar was pretty dilute, and my hydrogen peroxide was pretty dilute too, their combined power is pretty dang strong!
If you used the soaking method using vinegar or peracetic acid and have a good amount to dispose of, do not dump it in your garden where plants you care about are growing. Acids, such as vinegar, are often used as a natural weed killer. They&#;re environmentally &#;non toxic&#; because they break down quickly and have no lasting harm, but that doesn&#;t mean you want to water your favorite plants with it. Go ahead and give it to the weeds, if you want! We dumped our tubs in a mulched corner where no plants were growing.
I hope at least one of these non-toxic methods to sanitize garden and seedling supplies will work for you! Cheers, to disease-free seedlings.
If you liked this article, you may also enjoy:
The company is the world’s best Seedling Tray Machine Price supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.