Did I plant too early? When is the right time to plant in spring? There’s a bunch of different factors to take into consideration when talking about Spring planting. We’re talking about last frost dates. We’re talking about the weather forecast in your area around the time you’re thinking of planting. And there’s also some differences, whether we’re talking about planting out actual plants that maybe you’ve been growing indoors for a couple months or you’ve purchased at a local garden center or whether we’re talking about direct sowing seeds in the ground outside. Then there’s also this extra X factor of you and how much extra time and effort you could put into protecting these plants if you wanted to plant them out a little bit earlier.

On April 27, it snowed in our garden. The weather report only called for rain and cold temperatures, but the low was supposed to be around 40 degrees, and that did not happen. The garden beds with lettuce, radishes, beets, spinach, and mustard greens were only sowed several weeks ago, so everything is still pretty small. They did get covered in some snow before I got the cold frames on.

The snow peas also were covered in a decent amount of snow, but you could still see the green pea plants poking out. I have wire covering over the snow peas to keep squirrels from digging, so I threw some wool (from my wool mulch collection) on top to try to prevent any additional snow from coming down on the peas. And since the wool wouldn’t be directly on the peas, the snow would be able to melt off the peas easier.

I wasn’t expecting snow, and I shouldn’t be surprised because it’s not unheard of getting snow this time of year here. It’s really common in fact. But I looked at the weather forecast and it was rainy, it was cold, it was in the forties, but only a couple hours were really supposed to be in the high thirties, around 38 degrees fahrenheit.

One of the major things that we’re talking about when we’re talking about are we planting too early, is whether there is a risk of frost damage, and are our plants going to get damaged by snow? Those two things really go hand in hand, but they don’t have to happen together. We can get snow without frost and we can get frost without snow.

One of the big things that we talk about is our last frost date. Our last frost date is really the last day wherever we live where it’s likely that we’re going to see a frost. And that doesn’t mean that it won’t snow or we won’t get a frost after that date, but the likelihood is pretty low. I like to look at almanac.com for my last frost date as I find it to be the most accurate for my location. The dates are all populated based on historical data of your area calculated using 1991 to 2020 climate normals from NOAA. Your last frost date is important because frost is what has the ability to kill our plants the most, especially those new, young, tender plants.

But the last frost date isn’t everything. It’s a big part of the picture, but it’s based on historical data that gives us an estimate of when we might be able to plant things. We also need to look at the weather forecast when we’re deciding when is the right time to plant and what will it be able to survive. I have multiple weather apps, not relying on just one alone to get the most accurate information I can. Still, the weather forecast is the best guess as to what’s going to happen, and we can’t rely on that with certainty. So I lgive myself a buffer and insurance zone, if you will, of five to ten degrees.

If the low temperature is forecasted to be above 40 degrees for the day, I might only need a buffer about five degrees, anticipating that the temperature might actually be 5 degrees colder than forecasted. If the low temperature will be under 40 degrees, I’ll allow for a buffer of 10 degrees. This is because you have situations like we did this past weekend where rain and cold was forecasted, but it actually snowed when the temperature never got below 34 degrees. At high elevations, like where we are, it doesn’t have to be 32 degrees to snow. These five to ten degree buffer insurance policies generally keep me prepared for surprise snow and frosts.

The other reason why you want to account for a five to ten degree temperature difference is that the forecasted ambient temperature is warmer than the air right above the ground where our plants are growing, especially this time of year, where we have seedlings just popping up, or we have really young plants that we’re planting out.

But when the frost is gone, it still may not be time to plant just yet. A lot of plants are really not tolerant of cold weather. They might survive it, but they’re not going to thrive in it, and tomatoes are one of those crops. With tomatoes specifically, anything under 50 degrees is really going to stunt their growth and may end up taking them longer to catch up with other tomato plants that weren’t planted out until after the weather was warmer. (Tomatoes also stop growing if the temperature is over 85 degrees.) Melons, pumpkins, and eggplant, for a few other examples, are all crops that like it really hot, even hotter than tomatoes, so low temperatures must be consistently above 50 degrees before planting these out as well.

Now, on the other hand, cold hardy crops like dill and parsley, are probably going to be okay to plant out a few weeks before your last frost. You’d want to make sure you’re hardening off these plants, but they should be okay because they really like the cooler temperatures as they’re cool weather crops. They don’t need the heat like tomatoes or pumpkins or melons, so crops like that can actually do really well as long as the temperature is not going to drop too low. That’s because even if they are cold hardy crops, they’re young plants just starting to grow and get established and can be killed by frost.

When we’re talking about the hardiness of plants, we’re talking about after they’ve been established and growing for a season, going into the fall and winter. They’re not going to be able to survive 20 degrees now, but they can probably survive a light frost or even a little snow if hardened off. But heavy snow or large temperature drops and swings can still do damage to those plants.

So let’s go back out to the garden now and see how everything’s doing. I mean, it’s a couple days later, it’s 70 degrees out, and, you know, a few days ago, those plants were covered in some snow.

[00:21:14] Speaker B: Okay, so we’re back out here in the garden, and our garlic is looking just fine. And this is the lettuce bed that.

[00:21:25] Speaker A: I had thrown the cold frames on, but it had a significant amount of snow on here. This is just a little chicken wire to keep the squirrels out from digging until these plants get a little bit bigger. But they are looking really good.

Really good.

[00:21:48] Speaker B: Here we have radish and spinach, cool weather crops. Lettuce, radish, spinach, cool weather crops.

We’ve got some beets down here as well, and they are doing just fine.

[00:22:04] Speaker A: Everybody’s happy.

[00:22:06] Speaker B: This is the bed where we have.

[00:22:10] Speaker A: Snow peas planted in between the garlic.

And these guys are doing great.

They are growing like crazy, and they are going to need some support very soon here.

[00:22:34] Speaker B: I’m also really happy to see a lot of blossoms on the apple trees still and hopeful that we will get.

[00:22:50] Speaker A: A lot of apples this year.

Things are looking pretty good in the garden, and that’s because despite the cold temperatures and the snow that we had on Saturday, we have all cool weather crops out there right now. We don’t have anything that requires a lot of heat or that can be damaged by lower temperatures, as long as it’s not below freezing.

All the plants out there do enjoy cooler temperatures. Now, that doesn’t mean that they like the cold cold, right? They’re cool weather crops. So they still like these warm temperatures that we’re having right now during the day. The sixties, the seventies, they enjoy that, but they don’t need that, right? They’re gonna maybe grow faster in those temperatures, but they don’t need that. They’re still gonna grow, all right, in 40 degree or 50 degree temperatures. And they’re also plants that can handle some frost. They can be hardy. Peas, surprisingly, are actually hardy down to about 20 degrees fahrenheit, which, you know, it’s not something that’s really talked about too much, because we’re usually sowing them in spring, but they actually can be quite hardy. That doesn’t mean that you should plant them or sow the seeds, rather, you know, in February, if you live somewhere where it’s snowing a lot, just because you have temperatures above 20 degrees at night, when determining when you can sow the seeds for these cool weather crops, you have to think about a couple of different things. You know, just because they can tolerate the cold doesn’t mean that they’re actually going to do that very well when they’re young plants just trying to get established. Right. This warm weather that we’re having right now is really allowing them to get established and thrive and grow quickly. But if the temperatures are cooler, they’re going to grow a little bit slower. And if they don’t have a good established root system, if they don’t have a lot of foliage, then they’re not going to necessarily be able to withstand really cold temperatures because just a light frost could damage all of their foliage. I mean, a lot of plants that are hardy still get foliage damaged by frost. It’s really common. But if you have this big plant and you have a little bit of it that gets damaged, you can just cut that part off. Right. You just prune that plant. So you prune off the damaged part. And if you don’t prune it until spring, then what you’re doing is you’re keeping that damaged part on there to protect the rest of the part that’s not damaged by frost yet. And then once spring comes, you prune off that part, and then now it can just grow out more. But if you don’t have a lot of foliage, then that little part, the little seedling, that’s all you got. The whole thing can be damaged by frost just like that. Right. And so we don’t want to do that. So we definitely want to make sure that we’re planting later, not super early, just because we think these plants can handle the cold temperatures, because they can’t when they’re just trying to get established. But the other factor is that it’s almost kind of funny to think about, because we’re talking about these as cool weather crops. They like cool weather, but they need warm temperatures to germinate.

They just can’t germinate in cool temperatures. They really are going to take a lot longer to germinate. It’s going to be a lot slower, and so you’re just going to be waiting, and it’s going to be a waiting game, and they may never come up.

These plants actually like warm soils for germinating. I mean, most plants need warm soil for germinating. The exception is those plants that need stratification. They need cold in order to get the seed to do what it needs to do. Like garlic, for example. Garlic we plant in the fall because we need that clove to be able to split and divide into multiple cloves to form that big bulb. If we don’t give garlic that cold period it needs for stratification, then it’s still going to grow, but it’s just going to grow one big bulb. And so you’re not going to have all those individual cloves, which makes it harder to use up and, you know, keep fresh. So, you know, that’s the exception to the rule there where some, you know, seeds or plants, you know, because we’re not growing garlic from seeds, you know, however they reproduce, they need some sort of cold for stratification. But for most of the plants that we’re talking about in our vegetable gardens, just normal seed packet seeds, they need warmth in order to germinate, and they’re not going to germinate in really cold temperatures. So we have to think about soil temperatures.

Well, when we’re determining whether or not it’s the right time to plant or too early, let’s look at the soil temperatures that my garden has experienced in the last 90 days. So this line here is the soil temperature thermometer that I have in the soil out there. And on February 1, the soil sensor temperature average was 32.2 degrees fahrenheit.

The high and the low for the day was 32 to 32.7. And you can see on this graph, if you are watching the video podcast version, that the line here is actually showing you kind of the average, but the shadow that’s surrounding it is showing you the actual lows and highs for the day. So as we start getting into March, we start having an average soil temperature of 37.8 degrees fahrenheit. On March 8.

On March 21, our average soil temperature was 44.4 degrees fahrenheit, but the high soil temperature for that day was 53.2.

And as we started to get into April, our average soil temperatures were 47.2 degrees fahrenheit. On April 1 1st, 50 degrees, 50.5 degrees fahrenheit. On April 4. They’re kind of going back and forth here, you know, between about 47 and 50 something degrees.

We had that cold temperature this weekend, and our soil temperature on average that day was 48.7 degrees fahrenheit. But it’s pretty much stayed almost up to 50 degrees.

You know, right around there. It’s definitely gone above 50 degrees on a lot of these days, but it’s also been lower than that as well.

So you can kind of see how the soil temperatures change over time.

You know, I mean, back in February, we’re experiencing, you know, soil temperatures in the thirties, right? And they’re never really climbing into the forties until we start to get in March here. And then we start to get into some forties. And then by April, you know, we’re mid forties to fifties. But it’s not consistent day to day. It does change a lot. You can see here how much the graph goes up and down.

We’re in zone six a, so we get winter temperatures all the way down to negative ten degrees fahrenheit. And we actually just got bumped up to six a last year when they changed the zones for the country because the year before we were categorized as zone five b. And that doesn’t change anything. Our climate’s still the same. We’re still going to grow the same way that we’ve always grown before. All it really means is that the temperatures a decade ago were a couple degrees colder in the winter than they are now. So if you live somewhere, you know, close to where we are, or, you know, anywhere, really, as long as you’re not somewhere close to the equator, where you’re hot and sunny all year round, then you’re going to see these similar kind of trends in your soil temperatures if you’re tracking them as well. Right. In the winter, the fall and the winter, we start to gradually see the soil temperatures decrease. And then about mid winter, going into the spring, that’s when our soil temperatures start to increase. And so the average temperature is a little bit warmer from month to month. And now that we are, you know, in April, I mean, we’re about to be in May, but in April we experienced soil temperatures that were about 45 to 50 degrees. And, you know, you see a lot of seed packets or articles online that tells you certain crops can be planted or seeds sown as soon as the soil is workable or as soon as the soil is 50 degrees. And they’re kind of interchangeable, those things. I mean, workable just means that you can get in there and dig around and dig eight inches deep if you need to. And when the soil temperature at about four inches deep reaches 50 degrees on average, then you’re able to kind of work and get in there and the soil’s workable. So it all kind of works out around the same time, more or less. But does that mean that you should be sowing seeds now?

Well, yes, you could sow seeds once the soil has an average temperature of 50 degrees or more fahrenheit. Sure.

But, you know, you have different considerations there. And soil temperature is just one of those. So if you have a number of weeks still where there’s a big threat of frost or snow and you have these little seedlings that are popping out of the ground and they’re really tiny, then they’re going to be probably damaged by that snow or that frost if you get it. So you would have to have a plan in place to protect those seedlings in the event that you did get a frost or, you know, a lot of snow. So you could use things like cold frames like we have. You could use, you know, plant cloches or row covers. I mean, you can just, you know, pop like a bucket over a plant for nighttime, right. If that’s going to protect it enough from the snow and provide a little bit of insulation for it, that will keep it going, you could do that. So as long as you’re prepared to take those kinds of actions and protect your young plants, then sure, you can go on and sow those seeds now, by all means. But then there’s also a second consideration that’s kind of the flip side of that. Is, is that really warm enough to sow our seeds? I mean, let’s take the seeds that I have or the plants that I have growing in the garden that I direct sowed just a few weeks ago in this last month. One of them is the peas, the snow peas. And snow peas will germinate in colder temperatures, but they actually really like the soil temperature to be above 60 degrees in order to germinate. If it’s above 60 degrees, then they’ll germinate within like, a week, week and a half. If it’s not, if it’s lower than that, especially if it’s, like in the forties, which is, you know, kind of what we were looking at, right? Like around 45 degrees, average. If it’s that, then those snow peas could actually take three or four weeks to germinate and pop out of the ground. So that would actually delay things a lot.

If we have really wet soil, we’re increasing the chance of our seeds rotting, and then we also.

So what’s the point, right? If our seeds are going to rot, maybe, and we’re going to take a long time for them to come up, then why, then why would we sow? And why would we not just wait a couple weeks, and then they’ll grow fast at that point, and they’ll be at the same point as if we had sowed seeds earlier or maybe even ahead of those, if they’re growing and the ones that we sowed previously have all rotted. Right.

Lettuce is a similar crop in that way that it needs warm temperatures for the seeds to germinate. It can also germinate at lower temperatures. But the ideal temperature for lettuce to germinate is around 75 degrees fahrenheit. That’s really warm when we’re talking about early to mid spring. Right. So my soil temperatures have been climbing, you know, an average of ten or 15 degrees every month.

I mean, I don’t even know if they’re going to reach 75 degrees. Right. Like what?

So getting lettuce seeds to germinate, you know, could take a longer time when the soil is cold as well. And that, you know, might also be a consideration that you’d want to wait for the soil to warm up more so you can have a more consistent rate of germination and, you know, not have to worry about things not coming up or just sowing again later. But that being said, there’s a number of things that you can do if you’re prepared to take a little bit of extra effort and, you know, help those, those plants germinate. So one of the things that you can do is you can water in that soil with warm water. Now, if you have, like, a hose that you turn off so it doesn’t freeze during the winter, then, you know, then you know what I experience. And so I’m dragging watering cans back and forth from the house all a winter long, and I can just fill it up with warm water. You know, even if you’re not in particularly, you know, in particularly doing that, you could still just do it a couple times to get that particular soil where you’re going to sow your seeds. Warm, warm water makes the soil warm, right? Because it’s warm water we’re putting in there, so we’re getting a warmer temperature in there. But the other thing is that soil that’s dry, that doesn’t have any moisture in it, that’s typically colder. So if you have moisture in your soil, even if it’s, you know, just precipitation coming down from, you know, the sky, you know, that’s going to be cold this time of year, it’s not going to be warm or anything that’s still going to make your soil warmer than if you had dry soil because you had no precipitation at all. And moisture is something that just. It holds on to heat, right. Moist things, water, it allows, you know, heat to be trapped better. So wet, moist soil and even watering with warm water can bring up those soil temperatures, which can really help when seeds are germinating. Right. So that way, you’re already starting with warmer temperatures, and you can see a big spike in temperature of the soil from watering. With warm water, it can actually increase it really fast. Not that that’s going to stick around, you know, as the, you know, temperatures cool overnight and that sort of thing. But, you know, in the moment, it can really warm things up. Now, the second thing is you can cover your soil with mulch.

If you have seeds that are kind of really delicate, really small, like lettuce, that’s not going to work so much, you know, because those lettuce seeds, they need to come out and they need to be able to push out of the soil. And if you have a bunch of mulch that’s, like, big and in the way, that’s probably just not going to work too well. But plants like peas, they’re really sturdy when they come out, and they’re, they’re kind of big and bulky, so they’re actually able to push out through mulch quite easily. And one of the best mulch mulches that you can use is wool. Wool mulch. We’re going to talk about that in another episode.

But it is fabulous. And it’s just what it says. It’s wool. It’s sheep wool. And, I mean, that just is such a great insulator, and it really helps to keep that soil warm. So imagine if you watered your soil so it was moist, so it held on the heat better. You watered it with warm water so it brought up the temperature a little bit, and then you sowed your seeds in there, and then you covered it with wool mulch that just had this blanket protection of insulation on top, it’s really going to trap those temperatures a lot better than leaving that soil bare and uncovered. So those are some things that you could do to increase the temperature of the soil. You could also use cold frames. Right. Or row covers or plant cloches, any of that sort of stuff over the top anyway, as well. Right. So we can raise the soil temperatures. But then the second part, what you got to think about is, are these plants going to be able to survive? Right. We talked about them. If they’re small and young, they’re going to be really at risk for frost damage or just being damaged by heavy snow. So when we’re talking about planning out these cool weather crops, whether it’s an established plant that we’ve been growing inside the house, we got at the garden center, or if we’re going to sow some seeds directly in the soil.

Cool weather crops, we can definitely plant out before our last frost date. We can definitely plant out when there is going to be a little bit of frost, but we really want to watch the temperatures. We want to watch the weather report. We want to look for trends of, you know, weather going, you know, up warmer and not colder to really avoid the risk of a hard frost, which is also known as a killing frost. And so a hard frost is anything that is 28 degrees fahrenheit or under for four plus hours.

And, I mean, there’s a few different interpretations on that, but that’s kind of the standard rule of what a killing frost is, is if the temperature drops to 28 degrees or lower fahrenheit and it stays at that temperature or, you know, goes lower for 4 hours or more, then that is considered a hard frost or killing freeze, and tender plants won’t survive. Young crops, you know, that are just starting out, don’t have, you know, a lot of foliage or good root systems yet. Probably won’t survive. I mean, certainly if you’re protecting them in cold frames or row covers, they definitely can, but if you’re just having them out there exposed in the garden, probably not likely. I mean, you could try and some plants that are pretty hardy, you know, they might. They might do okay, but why risk it, right? I mean, maybe a couple. If you want to experiment, that’s always great, but I definitely wouldn’t do a whole crop, right, because we don’t want to lose a bunch of plants for no reason, you know, so you gotta make sure that you’re gonna avoid that, that there’s not gonna be any more hard frosts for the season. And so, generally, what we’re talking about is about three to four weeks before our last frost date.

If the temperatures are warm, you know, during the day, if the temperatures are not getting too low at night, if we’re mostly having periods of warmth, where then we dip down just for a couple days to some lower temperatures. If things are staying, you know, around the 35, 38 degree mark and, you know, continuously just getting a little bit warmer, then we’re probably good. But you gotta watch those weather forecasts. You gotta look out for that, and you gotta plan, you know, for what you’re gonna do if you do get a hard frost. So, you know, you gotta look at all those things and factor that in. And like I said, I mean, about three to four weeks before your last frost date is pretty probably the time that you can start to do these things.

So did we plant too early? I don’t think so. You know, the garden is looking good. The lettuce, radish, beets, spinach, peas, they’re all coming along. They’re all looking great. They’re all looking strong and healthy and lush.

The pea seeds were sown about four weeks before the last frost date here. The lettuce, radish, beet, spinach beds, those were sowed about six weeks or so before the last frost date, but they were sowed in cold frames, so they had that extra protection that the peas didn’t to, you know, keep them covered and protected from snow and frost so they were okay. And, you know, the pea seeds, we just waited until there was no more risk of a killing frost, which we can’t be certain about, but we can look at our, you know, weather forecast and make some educated guesses. So when is the right time to sow seeds, and when is the right time to plant out in spring?

It all depends.

It always depends. Everything depends. But if you, you know, take what we’ve talked about here today and implement it into your garden, then I think that you’ll find you can successfully have plants growing in your garden before your last frost, and you’ll know which plants to hold off on, like our tomatoes, which we still have several weeks to go, probably before we can plant out. But that’s all for now. We’ll see you on the next podcast.