Fall Garden Seed Starting Secrets - Ep. 257

Karin Velez [00:00:00]:
Fall is not just for raking leaves and pumpkin spice lattes. It is prime garden time. Now, I know it seems a little weird to talk about fall gardening already when it is hot as Hades outside, but if we're going to have a fall harvest, we have to plant in the summer. And oftentimes that means getting back to some indoor seed starting. But getting the timing spot on for this is kind of like threading a tiny little needle. And don't start seeds too early or you risk heat stress and bolting. But if you plant too late, you're racing frost and fading daylight hours and just incomplete harvests. It also gets trickier if you're gardening in a short season zone where your frost free window may be only 120 days.

Karin Velez [00:00:46]:
So today on Just Grow Something, we're going to go step by step through timing and executing an indoor seed starting soon strategy for the fall garden. We'll talk about the science behind fall nutrients and daylight changes. Countdown calendars going from your frost date back to your transplant date and back to your indoor sowing date. Fall garden crops that might be candidates for indoor seed starting based on their maturity, timing and their growth data. And then special strategies for you very short season growing areas. By the end, you'll have the tools you'll need to know when to get your seeds started indoors for your fall garden so you don't miss the window of opportunity. Let's dig in.

Karin Velez [00:01:55]:
So if you are on the email newsletter list, you will notice that last week's newsletter was a little bit different than what we have done in the past. And I am encouraging you, if you are not somebody who is already on this the newsletter to go ahead and get on that mailing list. I've done some switching around. It's no longer just sort of a recap of what's happening in the episodes or a gentle reminder that we released an episode. There's a little bit more information in there now and some, you know, fun tips and tricks and I'm trying to get a little bit more personal with you guys. So if you're not on the email list, Go ahead and go to my website justgrowsomething.com and you'll be able to find the sign up at the bottom of the page. If you did not sign start seeds indoors this past spring for your garden, but you are considering doing this for fall, or if you just didn't have very much success with your early indoor seed starts. My Seed to Sprout course is available on the courses page@justgrowsomething.com it's 20 bucks. It takes you through the proper containers and soil, heat mats and light requirements, proper planting techniques, growing them, on troubleshooting. I even have a bonus section in there on hardening off and there are downloadable resources. Again that's on the courses page@justgrowsomething.com I will also leave a link to that in the show notes. So why is fall sort of its own unique animal over the spring garden? Okay, so first a little science lesson. We need to calculate things a little bit differently in terms of our seeds starting in our planting dates for fall for a couple of different reasons.

Karin Velez [00:03:39]:
The first of these is temperature and heat stress. So our fall crops are going to be mainly cool season crops and they prefer daytime highs below 75 Fahrenheit and nights that are above 40 degrees Fahrenheit. So if you get higher than that, they start to get stressed out, they bolt. Basically, they head into their predict reproductive mode prematurely in the fall, even though our peak summer heat has waned. Right. Which is great. The plants get that sort of cool shoulder season to grow in after, you know, the summer heat. But there are a lot of temperature swings that happen.

Karin Velez [00:04:19]:
And so if we decide that we're going to plant directly in ground, that can actually delay germination. And those cooler temperatures that happen after that peak summer break, our heat breaks can actually slow our early growth rates. So there are some considerations between whether or not you're going to direct sow and whether or not you're going to transplant. And we want to time our plantings so that these crops mature as the days begin to cool and not earlier than that. The second consideration is the number of daylight hours and photoperiodism. Right. So as we shift from summer into the fall fall, the sun's daily path shortens. And so by late October in a lot of latitudes, a lot of the areas are falling below that 10 hours of daylight.

Karin Velez [00:05:10]:
We're a little bit later than that here, but not by much. And our research shows that photosynthesis slows dramatically once we get below that 10 hours so Elliot Coleman, who is sort of the father of four season gardening, termed this the Persephone period. And so, you know, that's what we'll just refer to it as the Persephone period. Once you hit that Persephone period, that, that daylight hours below 10, the growth rates slow, leaf production drops, root growth suffers. So when you're planting late, you know you're planting in the fall, as all these changes are happening, some plants may actually need almost double the amount of time to reach their harvest if they are planted too late. So this is a real thing, and it can really reduce your yield dramatically if you don't get the timing right. And then the third consideration is soil moisture and sort of your microclimate. So after it's been really hot all summer and we start to move into those cooler days, the soil just retains moisture better.

Karin Velez [00:06:23]:
You have lower evaporation. So that means we're, we're watering less, number one. And we also have sort of better early root growth. Now, of course, a lot of this can be mitigated in the summer garden with a lot of layers of mulch. But, you know, regardless of the mulch, those cooler temperatures are going to help facilitate this. And on the flip side of this, you know, if you live somewhere where your rainy season is the fall, those fall rains can also bring mold or just really wet soil consistently. And that can be kind of risky for young transplants. So you have to watch out for fungal diseases.

Karin Velez [00:07:01]:
And we also have to make sure that we're planting in well draining beds or raised areas if you are somewhere where you do get a lot of fall rain. So all of this translates into sort of the idea that fall gardening is more than just spring in reverse, right? It's, we're not just doing the opposite of what we did or repeating what we did in the spring. It really is its own season. And so we kind of have to recalibrate our timing and our variety selection and the way that we care for these fall crops. Now, don't let that scare you because I do maintain that the fall garden is a bit more hands off. It is not nearly as time intensive or labor intensive as the spring garden. In my experiences, there tend to be fewer weeds because just like those daylight hours are waning for the plants that we're trying to grow, it's also waiting for the weeds too. So that is also meaning that they are not growing as quickly as they normally would like they do in the spring in the summer garden.

Karin Velez [00:08:06]:
And also you have fewer of those weed seeds getting in there and sprouting as quickly. So that is very helpful. We also tend to see fewer pest issues as well. And let's be honest, when it starts to cool off a little bit out there, like, it just makes gardening a little bit more enjoyable. Right. So I am all about the fall garden. Just, we just have to understand that it really is its own season. It's not like a little, you know, repeat of spring, only in reverse.

Karin Velez [00:08:33]:
So the first thing that we have to do is sort of create this countdown method that tells us when it is that we're supposed to start our fall seedlings. And this generally begins if you are in an area that gets frost. We start with our frost dates. So most gardeners know what their last frost date is in the spring. Right, because we're all itching to get out there and get our first plants in the ground. And we're trying to make sure that, you know, they don't run the risk of. Of getting frosted before they get a chance to take off. If you've never gardened for fall, then you may not be paying as close of attention to your first frost date in the fall.

Karin Velez [00:09:19]:
So that's where we have to start. You need to know your zone's first frost date. So sources like your extension service are great ways to find this. You can go to the old Farmers Almanac online or any one of the climate tracker apps and find your average first frost date. This is the date where the temperatures dip to 32 degrees Fahrenheit or zero Celsius or below. So, for example, my zone typically sees the first frost right around October 20th or so. We'll see whether or not that moves a little bit this year. You know, our.

Karin Velez [00:09:54]:
Our last frost in the spring was way earlier than it normally has been, and that's been two years in a row now that that has happened. So I think last year I'd have to go back and check our notes, but. But I think last year our first hard frost was later than that October 20th date. So this is not a hard and fast. This is just a guideline to let you know, you know how to time when to get these crops in the ground, which helps you time when to get those seeds started. Okay. And this is going to tell you a couple of different things. You have to decide this based on what it is that you're growing, because some of these crops that you want to grow for the fall are perfectly fine with the fall frost.

Karin Velez [00:10:39]:
In fact, they taste better after they've had a frost. So this Frost date is just a point of reference for you for. Okay, yes. There are things that need to be to maturity before that date so you can get them harvested and out of the garden. Like lettuces that can't really handle a hard freeze. But if you have, you know, brassicas that are okay with a light frost or if you, if you have season extension, which we'll talk about here in a little bit. Have you had freeze. Frosted spinach, like spinach that has had frost is so much sweeter and is so much better than any other type of spinach.

Karin Velez [00:11:13]:
Carrots that have had the ground get really cold. You know, it concentrates those sugars and they just taste so much better. So this isn't saying that, oh gosh, the garden's going to be done at your first frost date. It just means you have to be cognizant of what that date is and know which crops need to go in when based on that date. Okay. And once we know that, then we are going to understand and when we start these crops. So the second, the second thing that we have to think about in this is understanding the days to maturity for what it is that we're going to grow. So this is usually printed on the seed packet and it's usually calibrated for optimal spring conditions.

Karin Velez [00:11:51]:
So those days that are lengthening and the soils that are warming, okay, that's speeding up the growth of those plants in the spring. The opposite is true for the fall garden. That growth is going to be slower. So our days to maturity isn't actually going to equal that sort of perfect spring timing anymore. So it's up to us to adjust it. So this is the fall buffer factor and the research and, you know, extension services and stuff basically have sort of given us these adjustments as fall approaches. And it's all based on the planting window before your first frost date. So if whatever it is that you're planting right has a maturity date, that means you are planting more than 11 weeks before your first frost date, then you generally only have to add about 10% to the number of days to maturity.

Karin Velez [00:12:46]:
Once you get to like that eight to 10 week time frame, then you're looking at a 20% buffer. For five to seven weeks, you're looking at a 40% buffer. So the closer we get to when those crops are planted near our frost date, the more days to maturity we have to add to that and understand how long it's going to take these crops to actually get to maturity. So let me, let me give you an Example of this to kind of help explain this, because I know it can be kind of confusing. And I'm going to put all of this information in the show notes. So. So when this episode is posted, you can go over to the website and you can go into the show notes and you will see all of this information in there. But essentially, if you have like spinach, and the spinach packet says that it gets to maturity in 45 days and your frost rate is like mine, it's October 20th.

Karin Velez [00:13:39]:
All right, well, 45 days is about six and a half weeks. That is in that five to seven week zone. Well, at five to seven weeks, we need to add a 40% buffer. Okay, so you've got 45 days. You know, multiply that by 40%, add it to the 45 days, and what do we have? We have 63 days. So if we are trying to harvest our spinach or have it to maturity by October 20th, that first frost date, so that we can continue to harvest after that. But we know it's going to be to maturity and we also know we're going to be losing our daylight hours, so there's not going to be a ton of growth after that. That.

Karin Velez [00:14:17]:
So our goal is to get the spinach to maturity by October 20th. Well, now we know it's going to take 63 days for that spinach to get to maturity, not the 45 days. So we have to start counting backwards from October 20th. Well, 63 days puts us at August 18th for an outdoor transplant date. If you're starting your seeds indoors, we also have to take into account growing the seedlings plus hardening them off before that August 18th date. So we have to add those extra days back in there so that we're not scrambling around because we still have to harden these plants off before they go out in the garden, just the same way that we do in the springtime. It's easy to sort of forget that step when we are planning when these seeds need to be started. Now, could you direct sow your spinach on that August 18th date? Yes, but you're likely going to miss the window a little bit.

Karin Velez [00:15:19]:
So I know we're talking all about indoor seed starting today, but keep this in mind too, that when you're deciding whether or not you're going to direct sow something or you're going to transplant something, you have to take into consideration that the number of days to maturity on a seed packet is from the time it either germinates. And I think generally speaking, they, they mean it. Germinates and it has its first set of true leaves. Right. Or for the transplant date or from the transplant date. So either way, even if you're direct sowing, you're still going to have to add some time back on that, that transplant date of August 18, because you have to account for how long it takes for that seed to germinate and get its first true leaves. So, so you're still probably having to add, you know, about 10 days there, which is about the same amount of time that you would have to add for your, for hardening off those seedlings. Okay.

Karin Velez [00:16:14]:
And the reason that those dates are very similar to each other is because when we transplant, we have to account for the transplant shock to happen because we know once we set those plants in, they're not going to immediately take off themselves, start growing again. No matter how well you have harvested them off, no matter harvested them, no matter how well you have hardened them off, and no matter how great the soil is, they still need to settle in. That takes 10 days, sometimes two weeks for them to start their growth again. So regardless of whether we're doing this directly sowing or we're, you know, trying to figure out a date for our indoor seed starting, the dates are going to be around the same. Okay. So let's just keep that in mind as we're talking about this process.

Karin Velez [00:18:33]:
So when we start to calculate these seed starting dates, I like to use a visual timeline of some sort. You can use a spreadsheet to figure this out. I just take my calendar out and I figure it out. So you go through and basically go onto your calendar and mark this date that you just figured out. Right. So August 18th was our spinach example. So then we're going to add our hardening off, you know, acclimatization sort of period there. So 10 to 14 days prior to transplanting for the seedlings to adapt to their outdoor, you know, light and weather conditions, I like to stick to about 10 days at the max, just because two weeks tends to, you know, sort of over harden them off and then that tends to get them a little bit more in terms of transplant shock. It's, it's kind of a weird phenomenon, but I like to stick with about 10 days. So that's going to bring your indoor seedlings finish date basically to August 8th. So that means you need to take into consideration the amount of time that takes for those seeds to germinate and how long it takes to grow them on. So to get their early growth and get those true leaf stages going.

Karin Velez [00:19:44]:
So we have that August 8th time frame of when we want to start hardening them off to get them outside. Now we have to take into consideration how long does it take to germinate? How long are we growing them on? Well, lettuce and spinach usually needs about four weeks, sometimes six weeks, depending on the conditions indoors to get germinated and get up and get growing and get those first few true leaves before you put them outside to harden off longer, you know, lived crops, or I should say crops that take longer to mature. Things like broccoli or cauliflower, we're generally looking at like six to eight weeks indoors. And then so like cabbages or things like that, that might be even longer, we're looking at eight to 12 weeks. So for spinach, you know, we're using spinach as our example, then we're going to want to count back six weeks from that Aug. 8 deadline of getting them finished and getting them to harden off, which puts us at June 26th as our indoor starting date, which I have already passed. So it's a good thing that I plan on just starting my seeds directly out in the garden. This is an option for you depending on what it is that you are growing.

Karin Velez [00:20:57]:
And obviously, there's a lot of things that you just really don't ever want to start indoors anyway that are just better started in place. But, you know, this is one of the things where how much time do you have to devote to getting the seeds started indoors? How much space do you have to devote at this time of the year to those seedlings? You can help to, you know, think about those things and figure out whether or not you're actually going to just start them directly in the ground. So instead of the June 27th indoor seed starting date, I am just moving forward and I am going to that August 8th date, and that's when I will direct sow my seeds. Okay, so let's use a different example. Maybe broccoli is a good one. If it's got 75 days to maturity, that's around 10 weeks or so. At that eight to 10 weeks before frost date, we end up adding a 20% buffer. Okay? So when we figure that out, we ends up being 90 days.

Karin Velez [00:21:56]:
So to figure out our target transplant date, we have that October 20th. We go back 90 days. That gives us a. A July 22nd date for transplanting. So then if we want those seeds to get six to eight weeks indoors to sprout and to get their first true leaves, and then we have to add the hardening off, then that means we're starting those seeds around late May to early June for our broccoli. Okay, so you see how this is working. You figure out how long it takes for. For them to get to maturity in the spring, figure out how many weeks that is.

Karin Velez [00:22:34]:
Go back through our list, our chart, and see, okay, how many weeks before frost, we're going to be planting those. We add that buffer to account for the slow growth because of the fall, and then we work backwards from that. So, you know, counting backwards from the days to maturity and accounting for our hardening off for about 10 days and how long it takes for us to start to sprout those seedlings and to grow them on. And of course, we kind of like to layer on successions in this, too. So if you're doing lettuce and you don't want all your lettuce coming on at once, you know, and we have successions like that, you can sow your lettuce every or start your lettuce every two to three weeks indoors so that you can Actually transplant them at those times that is appropriate for you so that you are harvesting every two to three weeks. It helps to sort of smooth the harvest out and it kind of hedges your bets a little bit for your timeline. So let's talk some specific plants. I group them by maturity and sort of complexity so that you can customize this based on your goals for your fast growing ones.

Karin Velez [00:23:38]:
The ones that mature 30 to 40 days or so, all of your baby greens, your lettuces, your arugula, these are all sort of our fall heroes. They are very quick, they are very forgiving, they are really good for success session sowing and they sort of balance out the garden a little bit because even if you're not interested in growing these to eat a ton of them, they also make really good trap crops for the other things that you might want to be growing. So those are maybe some of the ones that are in our sort of mid range here where it's like they take between 50 and 80 days to mature. Things like kale, Swiss chard, your broccoli, your cauliflower. You definitely want to plan that full buffer for these. And depending on where you are and what your first frost date is, they also also sometimes can do really well with some extra row cover or maybe some low tunnels that you can put over them especially to protect them, just post transplant to cover them or shade them a little bit. Because again, we're going to be planting these in the heat of the summertime and so we might need to give them a little bit extra protection and then you might need to put that protection back out there again once we get into that sort of frost time frame to be able to extend your season a little bit. We'll talk about here, that here in a second.

Karin Velez [00:24:55]:
And then you've got sort of longer season crops that are, you know, good for transplanting into the, the fall garden. Things like your cabbages and like your Brussels sprouts. Now if your zone is really short, like zone three or four, then you actually have to add an extra two to three weeks to that buffer. So these may actually need extra protection into the late fall to protect them from the really hard freezes in some of these zones. So let's talk to you, my short season gardeners, for those of you who only have fewer than 120 frost free days. So like zone three, zone four, right. This is all about you. The, the thing is you are likely going to have to start indoors early and often.

Karin Velez [00:25:36]:
So your long maturing groups crops are probably going to need about 12 to 14 weeks before for your first frost to really build those resilient seedlings and get them transplanted, even if these aren't ready for transplant until later, at least you have healthy stock ready when that window of opportunity kind of opens up. Season extension for you is really, really important. So utilizing row covers and cold frames and like little mini, you know, caterpillar tunnels or hoops, even if it just pushes your harvest window by like two weeks, that can actually make or break your things that maybe are late maturing. Like broccoli. You know, broccoli doesn't love a hard freeze. But if your season is really short and you need to get it in really early because you need that extra buffer time, they may not be ready by the time you start having your first few frosts. And so if you can use those row covers, that's going to extend your season a little bit and let you get that broccoli to maturity before it really starts to freeze hard. You also just may want to choose short season varieties or varieties that are suitable for overwintering.

Karin Velez [00:26:41]:
And a lot of times it'll say it on the packet that it's actually an overwintering variety. So, you know, if you're looking at spinach, you might choose like a Bloomsdale spinach that's only 45 days, or a flamenco kale that's only 55 days. Things that are really fast versus, you know, something that's like a 70 day heirloom or something like that, right? Go for those quick maturing varieties. And just remember, once that day length dips below 10 hours, we hit that Persephone period. Depending on your latitude, you're locked in, your growth is going to slow. So you either have to have matured those crops before this point or you need to have a little bit of a backup plan. So if the frost shows up but the soil hasn't frozen yet, you can continue to harvest those cold hardy greens like the kale and the shard or the collards, they'll actually keep until like down to negative 10 Fahrenheit if you keep them with some row covers. If this is not really, you know, relating to seed starting in terms of indoor seed starting.

Karin Velez [00:27:38]:
But if you're using like root crops like beets or carrots, you can actually kind of store those in place in the garden until that ground starts to freeze. Just use some heavy straw, mulch and some row covers. And then once the ground does start to freeze, then you can pull them and move them into cold storage. So that kind of extends your season a little bit too. But those aren't things that we're starting indoors or at least we shouldn't be starting indoors. And to transplant out the outside, those should definitely be planted directly into the soil. Regardless of where it is you are growing in terms of zone, how you're growing or how you garden does make a little bit of a difference. If you are gardening in in ground beds, know that that soil is going to start to cool down more quickly in the fall, which means that you can plant mid summer seedlings for the fall crops.

Karin Velez [00:28:27]:
And you want to kind of top your bed with some compost and some amendments like in the early, in early August to kind of get these things, your beds, prepared for these transplants. If you are in raised beds, you're gonna, your soil is going to continue to fluctuate quite a bit more. You know, those in the in ground beds have just more mass to them and so the heat from the rays from the sun are tending to dissipate a little bit better. When you're in raised beds and you have that lower volume of soil, it can fluctuate a lot more. So you have a really, really, really hot day and it's going to get hot. Generally speaking, you know those late summer rays are going to continue to keep that soil warmer. So keep in mind that if you are planting fast maturing crops like lettuces, they can handle being transplanted a little bit later in the summer to kind of protect them from a lot of that heat and that fluctuation. So it might be a few weeks later in a raised bed than it would be in an in ground bed just for the sake of the plants, honestly.

Karin Velez [00:29:35]:
And then if you are somebody who is growing in like small containers, this is actually kind of ideal because you can move them to the ideal locations for sunlight, but also for temperature future. So if you're transplanting into small containers that are movable, put those things in the shade and transplant your plants and slowly begin to move them out into that summer sun. For your fall crops you also can move them indoors. If you get to like your fall frost date and they're not ready yet, you can move them indoors and just kind of consider some supplemental light. You know, especially even if you're not in a frost area and but you get down below 10 hours a day, you hit that Persephone period and all that growth has slowed. Well, you might just bring them in the house and throw some cheap LEDs over top and boom, there you go. You get to extend your season. So I mentioned the broccoli and the window for seed starting being in early June and transplanting on July 22.

Karin Velez [00:30:38]:
The problem in my area is I have struggled with this year after year after year because it is still very, very hot here at the end of July. And I don't have a really good way historically to make sure that those seedlings get consistently watered while they're being settled in. And I often need to add some sun protection of some sort to protect them from sun scald during that time. And as a result of this, sometimes I have really great fall broccoli and cauliflower, and sometimes it does nothing at all. So this year I am direct sowing my brassicas in the late summer garden for a fall harvest. I'm going to be pulling back the straw mulch and amending the beds, putting the mulch back and just sort of making these pockets in the mulch where I'm going to direct. So I know that the germination is going to happen very, very quickly because that summer garden soil is still going to be very, very warm. It's almost akin to having the heat lats on in your seed starting area and warming that soil up to its ideal temperature when you plant.

Karin Velez [00:31:52]:
The same thing is going to happen out there in the summer garden with these warm temperatures. I just have to make sure that I keep that area watered enough while I'm waiting for those seeds to sprout, which should only take a few days given how warm it's going to be. So the mulch is going to help with that. And I do have a way to get the water then, and I think this is going to actually help reduce the amount of watering that I have to do after they have sprouted, because they're already going to be acclimated to the spaces where they sprout. Right. Versus having to wait a good two weeks as I water and kind of, you know, help mitigate that transplant shock in really scorching heat in late July. So that's what I'm going to do. I am going to, you know, work with doing some direct sewing instead of doing some transplanting of those crops.

Karin Velez [00:32:46]:
And I'm going to focus my transplants and my seed starting area solely towards the faster maturing things that I can put out there just a little bit later. So planting for fall is absolutely an experiment, I mean, from year to year to year. And so this is another way where you just kind of need to use your garden journal and figure out what worked well and what didn't and understand that this is a learning experience and not everything is going to go. I mean, it might go perfectly well for you the first time. I mean, I'd love that for you. But if experience has told me anything, that's not the way this is going to go. So don't get discouraged. Discouraged.

Karin Velez [00:33:25]:
If you try it and you go and transplant these plants and it's like, oh my gosh, they look awful and they all burn up. It's just a matter of figuring out the timing. But I promise you, the fall garden is absolutely worth it. Okay, so here's your summary. Look up your first frost date in the fall, Figure out what crops it is that you want to grow, and check their days to maturity. Adjust those dates to maturity based on that fall buffer percentage. I will list that in the show notes. Set your transplant deadline by counting back from that frost date and then add in that hardening off buffer.

Karin Velez [00:34:04]:
Plan your indoor sow date based on the seed to transplant time frame. And then if you need to use some season extenders to kind of stretch that harvest winter window out, just make sure that you are keeping notes of all of this, that you know where to go the next time. It's, it's easy to kind of pick, pinpoint what went wrong. And yes, of course, the weather can be unpredictable. And from one season to another, you know, your July or August temperatures may fluctuate quite a bit. But once you get the hang of this, you kind of know how long you can wait to get things into the garden before they get to maturity too late or how early you can get them in and, you know, really get them settled in and, and how much heat they can really stand. Right? So next week we're going to talk a little bit more about the summer garden and the successions that you can plant to keep that going right now. And then the following week, we're going to go back to talking about the fall garden.

Karin Velez [00:35:04]:
We're going to talk about your fall garden plan. I talk about the fall garden every year at this time, and I know it can sometimes be a big step for new gardeners or even experienced gardeners who have, like, never tried it before because it does take some planning and proper timing, but it really can be a great time of year to garden. So I hope, you know this episode has given you the confidence to kind of get some seeds started for the fall garden, whether you've got 200 growing days or just barely a couple, you know, a couple of weeks or a few weeks. The link to my seed to sprout course will be in the show. Notes that you can check that out. Until next time, my gardening friends. Keep on cultivating that dream garden, and we'll talk to you against it.