Minimum individual population sizes

2022-12-05T08:00:00Z
I would love to have a list of how many plants we should better have, for each species, to maintain a good landrace. I know that here we may have the attitude of ‘grow as much as you can, even if just 3 plants’, and I like that. But in terms of actually planning for the future, for good viability on the community level, I think there are probably harsher minimums if we are being realistic.

For example, on the article linked to in the ‘Inreeding Depression and our Food System’ page on the course (the article found here https://grain.org/article/entries/541-seed-laws-in-europe-locking-farmers-out# ), it states the following:

“Even if a farmer could reproduce seeds for his or her own use, individuals are often unable to maintain a variety. […] A market gardener cannot simultaneously reproduce several cross-pollinating varieties from one species and at the same time produce more seed from one variety than is needed (for cabbage, at least 50 plants are needed to produce seed and keep the diversity, which produces about one to two kilos of seed, yet a market gardener needs between 50 and 100 grams). Finally, nobody is safe from the loss of all seed, as a result of crop failure, for the next year’s plantings.”

I do not know if Joseph Lofthouse
you would agree with this 50 cabbages minimum for seed production? Either way it would be good to know for each species. And then, however harsh the results of that list would be, I would say that on the one hand, sure we can all do what we can in our own situation, but additionally it would seem to me a good idea to actually have regional centres where farms are specifically dedicated to growing at least this kind of minimum for each species, just for seed. Could grow significantly more of course, but just keep at least the minimum for seed harvest.

I suppose having distributed local networks is the other way of doing that, such that perhaps each local grower could grow whatever diversity they can - suppose even only harvesting seed from 5 plants each. 10 people makes 50 plants. And could perhaps then pool seeds and plant 80% of own seeds, 20% of the communal mix of seeds, for example. Hmm, yeah that could work well I guess. Nevertheless, I feel as if there would be advantage to having regional centres with the full minimum for each crop. And when I say ‘regional’, I mean like maybe 1 centre every 100km (i.e. 50km radius). So if we plan to set up such centres (or even distributed networks for that matter), such plant minimums would be rather important data to have.

Joseph Lofthouse
Those #-of -plants -charts are not applicable to landrace gardening.

There is more genetic diversity among the offspring of three unrelated cabbage plants than there is among the worldwide population of any named variety.

There is more genetic diversity in one package of my dry beans than there is in the seed catalogs of the top ten seed companies in the usa combined.

There is more genetic diversity in one cob of Astronomy Domine Sweet corn, than in all the commercial sweet corn grown in the usa combined.

I am not exaggerating. The extent of the inbreeding in heirlooms and hybrids is mind-boggling. It’s startling that the agricultural system has survived until now.

I am an advocate of doing what you can, and sharing with your local, and remote neighbors that are doing what they can.

Justin .
Oh ok, thanks. I guess that makes things a lot easier then! So was he just talking about how many plants to maintain a stable single phenotype population with sufficient diversity of genetics, whatever that would mean according to him, like as in the idea of a healthy heirloom population maybe? Otherwise I have no idea what he was talking about still now.

Emily S
Yeah, I think so. I think when you’re trying to preserve obvious diversity, you don’t need to be as concerned about population sizes, because the population sizes are there to make sure your super stable variety that looks all the same has some invisible genetic variations within it.

I noticed in one of Joseph Lofthouse’s videos (I think it was the one where he was tasting squash), he was going out of his way to preserve obvious genetic diversity when choosing which plants to save seeds from. For instance, “This squash is merely good, not superb, but it’s one of the few with a green rind, so I’ll save seeds from it just because I want to keep that trait in my squash population, for no other reason than it representing more genetic diversity.”

That seems like a clever approach to preserve genetic diversity with limited space to grow a population.

Joseph Lofthouse
We have known about the dangers of inbreeding since the Irish Potato famine, and people keep going down the inbreeding path. Then people get unhealthy highly inbred lines, and make up non-sense rules about how to keep inbreeding lines alive, while they loose half of their remaining diversity with each generation of inbreeding.

Wow! The closest that I have come to a rant since I deleted the nasty stuff I wrote about the seed industry in the rough draft of my book. Truly, the path to victory is not quarreling with evil, it is doing what we love.

Justin .
So here’s where my thoughts are going on this one. And bear in mind I have no experience so this is just me thinking theoretically. But, isn’t it rather more of a spectrum than a black and white situation?

For example, if I start out with some broccoli seeds from someone’s grex seeds, then great, I have more diversity than a commercial strain. Now the majority of the DNA will be the same - broccoli is broccoli! But if mine has been created by mixing 5 heirloom varieties and some crossing going on, then it is at least more diverse, more variations of some of the genes there.

But then, suppose out of 30 plants, if I only let 3 of my plants go to seed, I have instantly lost a large proportion of the genetic diversity. Especially so if those 3 happen to be siblings!

And it will only be a matter of time until my broccoli community becomes as inbred as an heirloom variety. So long as I am not inputting new genetics from outside of my system, I will inevitably loose genetics every year. Even if I let half my crop go to seed, this will be the case. Even if I let my entire crop go to seed, this will be the case, just slower, no?

I guess maybe that is why with traditional landraces around the world in non-Christian cultures, even whilst local varieties have been quite stable, they were still having an element of seed swapping over long distances.

But I guess what I was also thinking in this regard is that, the smaller our seed population, the faster we loose our genetic diversity. And whilst we are safe with people like you about Joseph, due to your large seed populations, for people who are isolated or become isolated, then there may be some importance in realising that the more individuals one collects seed from (so long as they are genetically different from each other), the further into the future one pushes genetic depression.

Joseph Lofthouse
I devote a whole chapter in the book to avoiding inbreeding depression. It’s not by chance that I come back again and again to the idea of community as essential to Landrace Gardening. This work is a community project, like it has always been, not something that a lone-wolf can accomplish or control.

Emily S
"Truly, the path to victory is not quarreling with evil, it is doing what we love. "

Yes. That. So much that. So well put!

Julia D
@Justin .
Don’t forget about many of the 50 cabbage plants that are contributing pollen and genetic diversity even if they don’t manage to produce seeds.

Joseph Lofthouse
I often find traits after 5 years that were the result of pollen released into the patch from plants that failed to produce seeds.

Justin .
Yeah I thought about pollen contributors and that’s reassuring for the species that cross a lot, though for those species for which crossing is rare, that will help less of course.

On that topic, for helping creating hybrid swarms, I was thinking of … maybe I can explain. Say I have 10 varieties. I was thinking to plant … let’s call it A, encircled by B~J. Like literally put it in the middle with one of each of the others on all sides. Make 10 such circles so that there’s a similar encircling of a B plant, a C plant, and so on. This way, for each circle, the central plant has the highest chance of crosses, of all kinds. Then keep only the seeds produced by the plant at the centre of each of circle, and… maybe plant at least 1 seed from each flower/fruit on those central plants.

I know that doesn’t include fitness selection. But as a means of trying to generate crosses quickly without doing it by hand, how does that sound
Joseph Lofthouse for the first year?

I also thought, if there were enough space, one could instead of doing 10 such circles, do… let’s say 30. The difference being… let’s call then set 1 (with those original 10 circles), then set 2 etc. up to in this case 3. In set 1, plant all the plants at the same time. But in set 2, plant the central plants 2 weeks earlier than the rest, and in set 3, the central plants 2 weeks later than the rest.

The gaps in planting could be more or less and one could do as many sets as one wanted. But the idea I’m getting at, is to account for difference in flowering times between varieties. Otherwise if flowering times differ enough, there are bound to be crosses that won’t happen. I don’t even know how much variance there is in flowering time between whichever varieties and in whichever species, but hopefully you get the idea of what I’m suggesting. How does that sound at maximising hybrid swarm generation?

Emily S
I seem to recall that Joseph Lofthouse pointed out somewhere that if you need a minimum of 50 plants, and you only have space for 10 every year, you can save seeds every year, and plant a few seeds from all of the last five years every time. That preserves the genetic diversity of 50 plants, even if you don’t have space for that many at one time.

I thought that was a clever idea. If you don’t have enough three-dimensional space, use the fourth dimension to effectively make it larger! :wink:

Joseph Lofthouse
And interchange seeds with your neighbors. (Landrace Gardening is about community). And gift seeds generously into the neighborhood, some of them will come back as pollen, or seeds, or fruits with seeds in them. Might be decades before they return, but they almost always return. We don’t have to be aware of the network, or what roles people or ecosystems play in it. Life lives, and finds it’s way back to diversity.

And plant a new variety from time to time.

And if you only have space for one full sized plant, plant ten plants in a clump.

And plant into the nearby wildlands.

Justin .
Ah yeah staggering seeds over the years sounds like a very clever way of getting around that!

And yeah, the distributed network of course.

Emily S
I’ve noticed that most good things are like that. (Love most of all.) The more you give away, the more you have. Yay!

And I love how much value in so little space is possible with seeds. That makes it very easy to store an abundance of diversity for every species you like growing.

Joseph Lofthouse
When I finally believed my own teachings, life got a lot simpler for me. Instead of having a room full of seeds, I now keep three crates of seeds, jumbled together by species. More diversity with less clutter.

Emily S
That’s a huge difference! Yay!

My current plan of action is to have two seed boxes. One is small and goes in my fridge. It has all of my personal seeds. I’ll put maybe 5% of every plant’s seed harvest in my personal box, and the rest in a giant box on my shelf. Half of the ones for sharing will be reserved for you guys, half for people in my local community. Something like that. I’m sure I’ll modify the percentages however it makes sense.

I may also start a tiny box for personal seeds in my chest freezer. That can be for seeds with a short lifespan, and/or seeds I want to keep archived for the far future.

J Larson
This is actually one of the things i’m most excited about with this group (and hopefully the mini more localized groups that will form from it). Each year we send in a bunch of our saved seeds (since it’s pretty easy to save 10 years of seeds every year). Then you take 25% or so from everyone elses seeds that we get back in return every year to keep things mixed up nicely. That way we’re constantly moving more and more diversity amongst the entire group, which gets other people’s trials make their way into our diversity and on and on.

Heidi A
I’m wondering, for those of us made cranky by too much math, if we couldn’t simply apply a concept my provider told me when my first baby was born that made a big impression on me: The mom is connected to the child – ask yourself, is my baby okay? If the answer is yes, then, don’t worry, your baby’s okay. There are interesting correlations on so many levels between tending lives, human or plant. If you’re planting a diverse landrace, maybe swapping some seed with friends or this group in whatever way that makes you feel happy, if your plants are doing well most of the time and you’re happy with them and your experience, then you probably have enough genetic diversity. If they begin to struggle or you begin experiencing angst, then invite in some more seed from a neighbor, library or larger group.

This doesn’t necessarily speak to the “marketability” of landrace seeds, but I’m also thinking that concept may be a completely separate mode of thought anyway (moot?) since that’s part of the system that has taken all of us out of older ways of knowing in the first place. It’s a challenge walking two paths going in different directions.

As a teacher of biology, trained as a biologist, exposed to various pedagogies, and now teaching young people about food, soil, biology, climate change, sustainability/regeneration in a garden, it’s becoming so starkly clear that our ‘systems’ even when well-meaning have so severely separated us from the very things we love - “nature”. I’m finding that I’m teaching myself an awful lot when I’m capable of handing over the reins, so to speak, of the outdoor classroom experience to the students – this is when they actually start ‘learning’ or knowing what I’m hoping they come to know. When I’m willing to scrap my very carefully planned activity because the students ask if they can go eat kale (ya, they really do) or flip logs for critters, they end up knowing more than if I feed them numbers, statistics, vocabulary, etc. (even though my own brain likes a certain amount of data…)

Anyway, I’m not totally sure I’m fully articulating the connections between these experiences, but I’m awfully sure they are there!

Emily S
And let’s remember that diversity of different species is desirable, too! That’s easy in a large growing space, but in a small one, it gets trickier. Companion crops that have similar needs and don’t compete for each other’s sunlight are the best way to accomplish that in small spaces.

One thing I would love to see, in a future year, is seed packets that have a mix of several species that have been grown together as companions by one gardener.

For instance, I’m going to try a drought tolerant modified three sisters bed next year, with sorghum, zucchinis that are used to being dry farmed (thanks, Lauren!), and vining tepary beans. If it works as well as well as I’m hoping, and I have enough seeds to share generously, I think distributing them together will give other gardeners the best chance of replicating that success in similar growing conditions, which would be very helpful to gardeners who have little water.

I’m sure there are other really great combinations, too. Distributing seeds from our favorite combinations together, along with specific notes about the growing conditions they’re used to, might be really useful.

Joseph Lofthouse
Lettuce (for seed) and vining beans work really well for me.

Beans on sunflower works better for me than beans on corn.

Justin .
yeah companion planting - love the idea of plants grown together being sold together, especially considering endophytes.

For the UK climate, what would be good to grow as a low growing plant among potatoes? And tomatoes? They seem quite tall so I’d love to know what munchies we could grow around them instead of having the ground/mulch bare.

One thing I was thinking of is wild garlic from Spring time. Wild garlic season is February and June. In a way maybe there’s no need to even grow it since I can harvest it wild. But still, maybe it’s worth it? Lovely food! And grows low. Would that be one good thing to grow as a ground cover in a bed of taller veg like potatoes? Have any of you guys ever grown it? I have some seeds from local wild ones and could also go gather some bulbs locally from the ground… Also up for all other suggestions, I don’t know anything about companion planting! (I have very little to unlearn about growing food in general :joy:)

Emily S
I know tomatoes and basil are another classic companion planting. Partly because you can harvest them together to make yummy sauce (grin), but also because strong smelling herbs have a tendency to drive away insect pests that are interested in tomatoes. So I’m thinking any strong-smelling herb that’s shade tolerant (which is, happily, most of them!) would do well under tomatoes. I grew garlic under my zucchinis this year, and they did fine.

Oh, yeah, and people say you “should” plant garlic in fall, but I planted mine in spring, and it was fine. I harvested a few, and the bulbs weren’t very big, so I left the rest in the ground. I might harvest them next year, or just let them get bigger. I’ve rea that if you don’t harvest garlic, it splits itself and turns into a clump of bulbs, basically a carefree perennial crop, which sounds pretty neat to me. :smiley:

My main goal with garlic this year was to use them as companion plants in shade under my squashes to a) sneak something else in, and b) maybe deter some bugs. So there was no opportunity cost to planting them in spring, rather than waiting till fall, for me. I might still harvest them in June, like people usually do with garlic. Or I might wait longer. Or I might harvest them sooner. Whenever! I’m thinking I’d like to treat them like perennials under my main crops that I harvest whenever I feel like it, because that will be the least amount of bother. (Grin.)

Of course, I really want to get my hands on some true garlic seeds and landrace them, too. And treat them the same way, and see which ones do awesome in shade with as little irrigation as possible. That would make them a terrific companion crop for me!

Ooh, and now I’m thinking that companion crop mixes that include true seeds for species that are usually cloned (garlic, potatoes, sweet potatoes, etc.) would be especially awesome . . .

Emily S
In general, shade tolerant small plants are often best to go under big tall plants, like tomatoes and squashes. I’ve heard lettuce and spinach are both good for that. Something like lettuce, which tends to do well in the spring and early summer (when squash and tomato plants are small), and then tends to die in the heat of summer anyway, thereby not needing any of the sunlight that is now shaded out, should be good. In theory, having sun while it’s cooler and shade when it’s hotter might even help lettuce survive a lot longer for you.

Anyway, just a thought! I haven’t tried it yet, but I probably will.

Emily S
@Mark Reed
Woot! “Fairly easy winter crop” sounds like what I’m hoping for. :smiley: What’s delightful is that broccoli is my favorite vegetable anyway (kohlrabi and cauliflower being close seconds – brassica oleracea flowers and stems are so yummy), and I don’t care about big heads, so a wildly mixed brassica oleracea landrace sounds delightful to me. I’m perfectly fine with other brassica species in there, too. Some of the seeds I strewed around randomly in my back garden are brassica rapa and brassica napus. I don’t particularly care about which species is which and whether they will all cross or not. Anything that gives me yummy food is welcome to get its seeds saved and replanted! :smiley:

I’m really hoping I can even induce them to turn into perennials that stay alive and flower for me year after year. I’ll get way more food that way. Which is why I quite naturally sowed a bunch of Homesteader’s Kaleidoscope perennial kale in my mix, along with lots of broccoli, cauliflower, kohlrabi, brussels sprouts, bok choy (rapa), Red Russian kale (rapa), and Russian Hunger Gap kale (napus). I didn’t bother with cabbage or collard greens or any other kales; I like brassica leaves just fine, but I want lots of flowers and stems (and brussels sprouts) far more than I want leaves.

In another bed about 100 feet away (not because I’m trying to prevent crossing; just because I had space there), I’ve got eleven fully grown kohlrabi plants overwintering in my side garden that I’m planning to let go to seed. They’re right next to four fully grown brussels sprouts plants that I’m planning to let go to seed. Assuming they survive (they look happy so far, and they’ve gone through quite a few 12-14 degree nights) and give me seeds next year, I’ll be happy to send you some kohlrabi / brussels sprouts crossed seeds. :wink: The ones in the other bed will probably mix in with them a bit, but they’ll probably be mostly crossing with each other. Should be interesting to see what results from that cross. Wouldn’t a brussels sprouts plant with lots of thick, juicy stems be awesome? :smiley:

Oh, good to know that daikon radish can’t handle the low 20s. We get temperatures in the low 10s, sometimes slightly lower (the lowest temperature last year was 9 degrees, which was the lowest we’d had in five years). So it sounds like daikons probably aren’t cold hardy enough for me to overwinter them. Darn. Well, any kind of radish that would be cold hardy enough would be fine. Anyone have a very cold hardy radish landrace? :wink:

Radish seed pods are delicious. The flower buds are really good, too. They taste really similar to broccoli. Broccoli’s better, but not by a huge margin. I probably won’t eat radish roots again unless I’m thinning them, because I’d much rather let them go to seed. (Grin.)

Ryder T
Ask me in a few years if I have any cold-hardy daikon-ish :slightly_smiling_face:. Planted them as a cover crop, they should winterkill but I wouldn’t call it a sure thing. Fukuoka said his daikon basically took care of itself, which in the context to me meant a lot of it overwintered. I’d have to check to know for sure, but I’d expect Fukuoka’s winters to be at least comparably cold to zone 7 if not colder.

I’m sure somebody’s got a radish already up to the task, but on the plant community note, Fukuoka tended to grow his vegetables “wild” in his orchards. I wonder, were these daikon just adapted to the cold or did the vegetable community remember and help each other? Did the trees help them survive the winter?

Ever since reading an excerpt from Robin Wall Kimmerer’s essay on serviceberries, I’ve been obsessed by the idea that not only might mother trees nurse young trees, they might do the same for other plants, even perhaps to the point of nursing an annual plant through the winter as though it were perennial. That quote was from a indigenous hunter asked why he had invited his extended family and community to a feast rather than store his meat. The hunter replied, “I store my meat in the belly of my brother”.

Heidi A
I have had daikon radish in winter cover crops (home with below 0 and school with 15F lows), but haven’t been paying attention to it much in regards to overwintering. (Wheat, vetch, and the Austrian winter peas are stellar even at home temps. I had lettuce make it through last year at home. I have no idea how – and yes I saved seed!) I feel like we’ve had some overwintering at school… I know radishes and turnip seed that I broadcast in fall for winter cover crop often doesn’t germinate right away, but then comes up “on its own” in the very early spring and grows great. The students loved harvesting huge yummy turnips so much that I didn’t have the heart to deny them the experience and save any to go to seed this year. Who knew a turnip hunt could produce so much joy? I’ll have to plant them and hide them in inconspicuous side areas in the future!

Baker Creek has had a variety of ‘winter’ radish called ‘Shawo’ that might be a good addition to getting an overwintering radish landrace. Misato Rose radish overwintered at school when planted in August-ish.

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One of the difficulties for me with cool season crops is that I have such short springs that it’s tough to get the plants big before blazing hot summer begins, and I have such short autumns that it’s tough to get them the plants big before it starts snowing.

Despite sowing loads of brassica seeds in July, August, and September, none of my brassica seeds sprouted until early October. (Slaps forehead.) And they were covered in snow three weeks later.

So especially cold hardy crops that can keep growing through the winter, even while tiny little seedlings, seems like the best solution to that issue.

I could also go in the other direction and look for heat-tolerant varieties, but I have loads of options for warm season crops, and very little space. So I want to use my garden beds through the winter, and especially hardy cold season crops seems like the ideal way to go.

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Going back to the original topic of this thread: I’d guess that so long as a population of plants had visible diversity (different colors, leaf shapes, etc.) it has to be much less inbred than a standard OP variety, and so hasn’t been inbred to a damaging degree. Small population sizes might be OK if people carefully saved a range of diverse individuals every year to form the basis of the next year’s population.

(In the same way, in the first year of growing plants to cross, one only really needs on plant of each variety, since the hybridization and subsequent segregation will generate an order of magnitude more diversity than would be found between individuals of the same variety.)

But that’s just a guess, and I’m not sure if it is totally accurate.

A different reason to favor larger population sizes is that it becomes more likely to find unusual genetic combinations with a larger population; unlikely events are more likely to show up given enough plants (and enough time to look for them.)

So long as we’re all swapping seeds around through GtS, population sizes aren’t probably anything to worry about; we’ve all got an enormous effective population size.

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Just found this thread…as long as each of us saves seed and shares, the diversity should prevail. My garden grows hundreds of celery plants…but only a few tomatos. I dont worry, just keep growing.
I have companion seed mixes, i wasnt careful about separating seeds when collecting them. Malabar spinach, cilantro, dill and edible chrysanthemum mixed seed, all grew together well and all the seed ended up mixed together in the same jar. Its easier to plant, they go in together at the same time for sowing. The dill is a mix of 4 varieties, the chrysanthemum has two varieties and the cilantro 3 varieties.

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I’ve often thought that companion crop mixes like that would be cool to share with other people. If those species have been grown together for at least a generation and thrived that way, it makes sense to keep each generation in the same polyculture it thrives in; I bet every generation would become more and more comfortable together as a thriving community.

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So far it works better to grow the companion mixes in the dry and hot climate. Every season something weird will happen, but at least something grows out to produce seeds. Keeping the ground covered works well and Im happy when its a mix of edible greens or herbs.

Yeah, exactly! I’ve decided I want everything to be a polyculture. That way, if one particular crop fails, no worry, there’s already something else tasty sown in that space that will do well.

Since winter and summer are two very different growing seasons for me, I’m also thinking I want to have a perennial polyculture of dormant-in-winter and dormant-in-summer plants. One of my neighbors has a bed that transitions itself from all-tulips into all-echinecea without her putting forth any effort, and I think that’s a great system. I really want to take her idea and run with it. :wink:

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That sounds like an excellent idea. Does it typically get cold in winter, like zero F or below now and then. Does it snow much?

We usually get one night that hits 9 degrees F. Maybe two. Every two years or so, we’ll get a night that hits 7 degrees F. In February 2022, there was a massive blizzard that gave us 3 degrees F for one night, which was our coldest temperature in 20 years.

I’d say about 10 of our winter nights per year are between 12-15 degrees F.

Most of the rest of our winter nights are between 15-25 degrees F.

Our winter days are much warmer. 90% of them are above freezing. Most are somewhere between 40-80 degrees F, depending on how many clouds there are that day.

It’s rare for the ground to fully freeze. The top two or three inches might freeze on the coldest, but because it will thaw every morning, the soil underneath that rarely freezes. Even after the coldest nights, you can take a shovel and jab out a circle of frozen soil and then finds lots of (very cold) mud underneath.

We get 18 inches of precipitation a year, most of it in the winter. So, as you would expect, we get snow at night and rain during the day. (Sometimes the reverse, but not often.) When it snows at night, we can usually expect it to melt by the end of the next day.

The most annoying thing about winter gardening is mud. As in, lots of it. Everywhere. All the time. Deep wood chip mulch helps alleviate that problem. :wink: It also makes it way easier to access the soil if the top few inches are wood chips, because if the inches of wood chips freeze solid, it’s still easy to dig through them to get to the soil.

Things grow slower in winter, which is the biggest downside, and there are some days that are just too cold to set foot out there, but I overall consider winter a very pleasant growing season, significantly easier than summer (which is very hot, very dry, and there are oodles of bugs and vast quantities of bindweed).

I keep trying to tell other gardeners around me that the garden doesn’t have to be over once the first frost hits – in fact, winter gardening is easier. You just have to grow different plants. :wink: You can’t grow peas in the summer here; you can’t grow squashes in the winter. But you can grow them both; they just belong in opposite seasons.

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I needed to hear this today. Looking forward to doing more of what I love instead of focusing so much on what evil is doing.