You’re Hardening Off Wrong

Added: 2026-05-12

[00:00:00]Stop harding off your seedlings like it's a freaking punishment camp. You guys are making it seem like a plant has a watch and somehow if you put it out for one 2 3 hours, it's going to become brave. And that's so far from the truth because plants don't own watches in case you didn't get the memo. And punishing them actually is setting you back enormously. So please, for the love of God, stop. Plants literally respond to a select number of things. light intensity, wind, water loss, temperature, and in the soil, as well as stom model control. If you suddenly just ramp up time, regardless of the stress you're placing your plant in, you're going to have those kind of really sad looking plants, because what we're trying to control in all actuality is the stress exposure, not the time exposure. So today's video, we're actually going to harden off or give you a prescription for hardening off based completely and entirely on plant physiology. And if you're wondering why, it's because I have a bachelor's of science and so science with a minor in plant science. And I like to take all of that science and apply it to plants in the garden cuz that's what you do with a very expensive degree. I do want to say one thing really quick. It was my dad's birthday this weekend and my sister sent me a photo of my dad with the Gardening in Canada coffee mug, which apparently is absolutely awesome. And I heard a little rumor. I didn't know this was true, but dad, I love you. You are adorable. Apparently, he's like my biggest fan. And he takes his laptop and he sits and he watches gardening in Canada like nearly every single day.

[00:01:38]like he watches the backlog if I didn't release a video that day because I release it three times a week. He doesn't even have a garden at all. So, hi dad. Thank you for watching me. Thank you for supporting me with a coffee mug that I'm sure you did not need. I means the world to me. And with that being said, if you want to join my dad and a 150ish thousand odd other people, hit that subscribe button cuz it means a lot. AI is taking over the internet. And so there's a lot of really terrible gardening tips out of there out there that don't revolve around reality at all, such as really high winds and cool temps after 25° and sunny yesterday. And so if you want real time gardening, then subscribe button, hit it. You're supporting a real person. It's a free, simple, kind thing to do if you are enjoying this content. So number one is that your seedlings are not weak.

[00:02:26]They're adapted to really high humidity, the perfect settings of light, the perfect soil moisture, maybe even the perfect gentle wind gust, not a prairie plow wind that's going to send it into next Thursday. So, what we tend to do with these little guys is we tend to say, "Go free, build character, just like our parents told us when we were younger and not wanting to get our first jobs." And ultimately where we seem to have survived planes tend to get stressed out a little haggarded and they don't come back as strong. So the number one thing that happens is actually called photo inhibition aka the sun slap syndrome as I like to call it. That is not a technical term whatsoever. Photo inhibition very simply put is when there is too much light on the plant and the plant does not have the photosynthetic receptors to be able to process said light which in turn causes that kind of burning that we see or this wilting or kind of shrinking down that sort of thing. So to avoid that we don't want to just simply throw them into the sun even if it's for an hour. We don't want direct sunlight even for 30 minutes to build character if you will because we don't want to have photo inhibition. We want our photosynthetic rate to stay where it is, go down and then climb if you will. Next up is the changes in stomatal conductance as we like to call it aka the process of stomatal acclamation. So stomata if you do not know what that is are kind of these lip looking things for lack of a better term. The amount of stomatas that a plant has actually is highly dependent on like a C3 or C4 plant. That's a totally different video unto itself. But what these stomata do is they breathe.

[00:04:11]So they let CO2 in, oxygen out, and in turn that allows for photosynthesis to take place. It's quite literally an equation that needs to work in harmony.

[00:04:21]So we need photosynthesis, the introduction of light combined with functioning stomatas. We know that these are heavily heavily controlled by not so much humidity but the intensity of light combined with the light pattern or length. So stomata notoriously will open mostly during the night. The reason being is that light is intense and light dehydrates. So to avoid excessive levels of dehydration, the stomata stay closed until that light disappears or that intensity decreases.

[00:05:04]Then the stomata tend to open up. What this means is that if your plant is kind of adjusted to a pattern that you've designed via your plant lights and you simply go in and just ram it into full sun with a ton of wind, it's going there's going to be a lag there. And that leg, depending on how long it takes, can actually result in a very sick plant or a plant that completely shuts down in growth because now it's got to reestablish its patterns and feel figure out what's going on or more importantly it can't change its pattern because it can't do it just like that and therefore the plant itself starts to struggle and it has no way of coming back from that quick enough to be able to overcome the issue. So your classic kind of hardening off schedule can look something like this. Day 1, 1 hour outside, day 2, 2 hours outside, 3, 3 hours. You get the idea. And you would continue this process over a week, maybe 2 weeks depending. But the reality is it doesn't respond to a watch like we discussed before. What it does respond to is the intensity and the combination of stressors it's exposed to. So 1 hour of really bright light can actually cause more issues than 6 hours of complete shade for example. So what I like to do is what I call the ramp up method. I also can use something like the bucket method which I would probably character I call it the bucket method because that's just I didn't so my this is my grandma's hand-me-down. This is not like science at all. This is grandma's handy down hand-me-down. And I've just used it for years religiously on all plans and it works fabulously. I will not lie. But I guess you could call the bucket method also like slow transition method if you will. But let's talk about the gradual method first because maybe not you guys maybe don't have access to unlimited buckets just everywhere. So, the way that this would look if you were going to do like a really slow ramp up method would be to day one and day two expose your plant to shade, not violent ultra UV exposure like you are trying to burn a red head at this stake type thing. So, in that case, what you may want to do is you may want to put it outdoors under a tree up against the house where there is shade.

[00:07:21]You want to keep this plant in shade all day nonstop. We're not talking deep shade, so it's like cold. We're talking shade, like shade type thing. And you're going to leave them out there all day.

[00:07:32]You're going to put them out in the morning. You're going to go home and you're going to forget about them till you get home that night. But you just really, really, really, please, for the love of God, do not in any capacity expose it to excessive levels of wind or anything like that. You need to shelter it in some way. So, if that involves putting freaking plastic bags up to protect it from wind, then do it because we don't want the wind yet. We just want this kind of really nuanced light exposure. So, day three and four, you could technically start giving them some sun exposure. We're talking like morning sun only inside by 10:30 a.m. type thing. So, if I was to do this in a world where everybody has to work Monday to Friday, I'd probably start my harding off process on like Wednesday or Thursday and I would do Wednesday, Thursday, Friday outdoors in shade. And then I would do the third and the fourth day or the fourth and the fifth day in the morning sunlight. So, on the weekend and then you're going to pull it right back in the shade. You're not going to put them in the greenhouse or put them away. You're just going to put them back in that shady spot. Day five or six, I would do kind of lighter intensity sun, maybe a little bit less shade. If you can position them in a way that you know it gets morning sun and then the eventually shade will take over, that's ideal. And we want them to get like a little bit more exposure to kind of the wind and that sort of thing. Not gale force, but we just want that kind of light breeze exposure if possible. After that, what you're going to do is you're going to expose the plant to just regular old exposure. So, you're going to expose it to the amount of sunlight it would normally get. And you're going to watch it and ensure that it's still growing and it's still happy and it's healthy. It's not limp. It's not looking trashed. It's not looking anything like that. If it does, you need to give it time to recuperate before putting it in the ground because the container itself is going to be warmer just naturally.

[00:09:21]Less soil, less water holding capacity.

[00:09:24]you know, a darker black container if it is that will help keep those roots warmer, which is less of a stressor for that plant. It also still gives you the option of pulling that plant back away from wind, away from intense light before putting it outdoors. You put it outdoors, it is now at the whim of mother nature, and she cannot control that. So, we want to just wait to see if everything looks happy and healthy. If you do this gradually enough and you protect them enough, by day seven, your plant should look almost identical to the way it did on day one. And that's what we are looking for. We don't need to look like it was ran into battle with Alexander grade on its back type situation that we don't need at all.

[00:10:04]Now, my slow transition method, if you will, I personally am a fan of and that is what I ultimately do use. So, you can see my plants are inside of a greenhouse and they stay in here till they go and they get planted directly outdoors. I will, for all transparency sake, I do have a very large fan that I have off right now cuz it's also very, very loud.

[00:10:24]I grabbed this off Amazon. It wasn't that expensive. This is what it looks like. So, this bad boy goes in here and I actually kind of angle it on a bucket upwards so it forces the air up and then it kind of trashes down on the plants.

[00:10:36]And I put it on a pretty high setting. I can physically see my plants moving, if you will. And I will run this day and night. I have a heater, so ambiently, soil temp wise, it's a little bit warmer. I have these lights, which are intense. If I was to have a plant directly under this, I would roast it entirely. But I do have these in here because I don't have super intense light on this. And then during the day, it's not that warm out today. It's not going to be warm up for the rest of the week, but it's going to be above that 10° mark. And so, what I will do is I will open the door that you guys are sitting in right now. And then I also will open the window which in turn will allow wind cooler air in bugs that sort of thing.

[00:11:20]All of which will help to harden these guys off. From here, like I said, they go directly into the garden. So, I put them in the garden and I put a bucket over top. There's a hole in the bottom of the bucket and I literally just grind it in. And this allows me to spot water it. And so I water directly in the spot that the seedling is in, which actually prevents weed emergence around that plant for a small period of time.

[00:11:42]They're black buckets mostly, some are white, but the black buckets in particular are a heat sink. So they actually pull that heat in. So it mimics something similar to what this greenhouse temperature is. And then it also blocks against wind and it provides shade. Now you can leave these buckets on. You can leave the buckets on all year. that will in turn again intensify heat which in the case of something like cabbage or celery or broccoli or cauliflower or kale probably not a great idea. So for those guys I don't encourage this process and I actually would take the buckets off once I begin to see some new growth. But for the other guys you can leave them on because that heat is helpful. Now what I'm looking for when I have the buckets on and I'm doing the slow transition method if you will is I'm looking for new growth. So, the buckets stay on until I see that the leaves are putting on or the plant is putting on new leaves. And once I see those new leaves emerge, I know that my roots are fine, my plant is fine, the bucket can come off, and the plant is a-ok. Okay. There's no burning.

[00:12:40]There's nothing crazy like that. So, give that a shot. And if you're wondering what to start in the garden here in May, check out this video right there. And that is what Google says you should watch next. I will talk to you guys next time. Thanks.