• Post Reply Bookmark Topic Watch Topic
  • New Topic
permaculture forums growies critters building homesteading energy monies living kitchen purity ungarbage community wilderness fiber arts art permaculture artisans regional education experiences global resources the cider press projects digital market permies.com all forums
this forum made possible by our volunteer staff, including ...
master stewards:
  • Nicole Alderman
  • raven ranson
stewards:
  • paul wheaton
  • Jocelyn Campbell
  • Julia Winter
garden masters:
  • Anne Miller
  • Pearl Sutton
  • thomas rubino
  • Bill Crim
  • Kim Goodwin
  • Joylynn Hardesty
gardeners:
  • Amit Enventres
  • Mike Jay
  • Dan Boone

Do raised beds actually prolong your growing season?  RSS feed

 
Posts: 8
  • Likes 2
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Hey folks, a question on a bit of garden wisdom I've read over and over.

A handful of different gardening books I've read mention that raised beds can improve drainage, are easier to add amendments to, manage weeds in, etc. Fair enough, I won't contest that. However, many of them have also claimed that in cooler regions, raised beds allow you to get an earlier start on the growing season since the soil warms up faster. Okay...again, I'm not going to argue that the soil warms up faster. If you pile some soil up above ground level it makes sense that it'd warm faster, as it has less connection with the thermal mass of the rest of the earth.

But does it actually extend the season? Surely if it warms up faster, it also cools down faster at the end of the season? Wouldn't any additional days in spring be negated by lost days in fall due to this more rapid cooling? It seems more like daylight savings than anything else.

Is this the case? Am I missing something? What's your experience with raised beds and season extension?
Appreciate any and all info!
 
pollinator
Posts: 1820
Location: Toronto, Ontario
125
bee forest garden fungi hugelkultur cooking rabbit trees urban wofati
  • Likes 3
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Hi Lia.

My most successful experience was with a hugelbeet I built in my parents' back yard in Toronto. I dug it 3 feet below grade, buried two manitoba maple corpses in it, as well as lots of woody debris, years of leaf litter accumulation, gutter cleanings, two years of coffee ground-heavy compost, and bags of composted cow manure. To this I added a three foot trench worth of dirt, which I filled in with wood chips and inoculated with a mushroom slurry, and 3ish inches of wood chip mulch on the top of the hugelbeet. The wood chips were from an urban arbourist, and so exclusively ramial wood, so it brought its own nitrogen along with it. It was 3 feet wide, 18 feet long, and six feet in total height, being 3 feet below grade. The sides were vertical, and held together with a box made of 2.5 foot by 3 foot pallets wired together for the top 3 feet, and the bottom having been backfilled with wood chips.

With a large quantity of buried whole wood and manure, I experienced an almost constant heating effect throughout the winter in the first and second years. I was in 6b, and while we see humid, 30 C plus summer days, we can also see -30 C winters.

In the summer, my beans and squash did really well, and anything that preferred cool soil conditions died. I harvested many butternut squash longer than my forearm from compost volunteers I hadn't noticed.

In the winter, it was the only patch growing anything, and that was kale and beets and mints, with some baby field greens and snow peas. It was the only patch devoid of snow.

I had to abandon that bed for logistical reasons, but I suspect as the buried wood broke down, the heating effect would minimise.

To answer the question directly, it depends. I had an issue with my bed being too tall without sufficient soil cover to withstand dessication in a seasonal dry spell, and so found myself watering daily to keep things alive. Things can go wrong, and hugelbeets are a tool that, I think, must be catered to the individual situation and need.

I think that a raised bed in conjunction with a cold frame or row tunnel cover thingie is probably going to out-perform the cold frame or row tunnel cover thingie on its own, provided the raised bed is designed with that in mind. Although I have to say, taking the simple example of insulating the walls of a ground-connected planter, it seems that insulation would at once be great for trapping heat to lengthen the season, and terrible for allowing the warm spring air to raise the temperature of the soil in the insulated planter.

But perhaps that's where the cold frame or row tunnel cover thingie comes in.

-CK
 
gardener
Posts: 1219
Location: Middle Tennessee
193
books cat chicken food preservation homestead cooking purity trees
  • Likes 1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Hey Lia-

I garden in raised beds and can offer my thoughts as far as them extending a growing season. Chris brought up a great point in that a raised bed in conjunction with a cold frame or low tunnel is really what provides the season extending capabilities. So my raised beds that I don't have covers on, like you mentioned, do warm a little faster than the earth below, but also tend to cool faster it seems. My raised beds that I have tunnel covers on is where I get season extension. Granted I'm in the south, in Tennessee zone 7a, but we still get a winter here, and my covered beds stay warmer than my other uncovered beds. The only crops I have growing during late fall and winter are of course the frost tolerant crops such as brassicas, kales, spinach, lettuce, etc. The lettuces are a good example, as the uncovered ones get nipped pretty hard when it freezes, but my lettuces in a covered bed at the same time are untouched by frost and look great. It has to drop into the mid-low twenties for my covered lettuce to show signs of frostbite. The spinaches on the other hand are much more freeze hardy. My uncovered spinaches look fine at 25(f) degrees and appear the the same as the covered ones. When it drops to about 20 degrees, then the uncovered spinach starts to get unhappy and show frostbite, whereas the covered ones don't. Each year so far since I've had my covered raised beds, I'm still pulling lettuce and spinach from the garden in December, and can sow seeds for the same in February.

Cold frames and covers such as tunnels have been the real season extender for me.
 
Posts: 944
Location: Graham, Washington [Zone 7b, 47.041 Latitude] 41inches average annual rainfall, cool summer drought
31
  • Likes 2
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
With many vegetables the mature plant is far more tolerant of cold soil than seeds or seedlings.

For example I have had tomato plants survive and continue to ripen their fruit into october with night time lows in the low forties.

Weeks gained from warmer soil in the spring for seeds and seedlings more than offsets any loss in the end of the season with mature plants - in most cases. (Exceptions will exist of course.)
 
gardener
Posts: 4890
Location: Vilonia, Arkansas - Zone 7B/8A stoney, sandy loam soil pH 6.5
564
books chicken dog duck fish forest garden fungi homestead hugelkultur hunting pig
  • Likes 1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
As Kyrt mentioned extra length of time for raised beds comes from plant maturity with a few variables.

I am in USDA Zone 8a and we use raised beds for most of our vegetables.
These raised beds do several things for our growing season.
They give us the ability to start earlier by using cold frames over the beds for in the bed seed starting.
They give us microclimates for wider variety of what we can grow in the early, mid and late season.
They also give us easier access to the plants for care taking and harvesting (we are not as young as we used to be).

It is easier to make additions of compost, mulch, compost teas so maintenance is easier on us.

Last year our tomato crop started in May and ended in December, partly because of the raised beds and partly because of the warm weather lasting until after Christmas.
We finally just shut the plants down (pulled them up) because we got two frosts, Dec. 28th and Dec 30th, which wiped out the last set of tomatoes.

By the way, we use Straw Bales for many of our vegetables so we don't have to water unless we fail to get a rain in a two week period.

Redhawk
 
pollinator
Posts: 1361
Location: cool climate, Blue Mountains, Australia
16
  • Likes 1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I would look for the source of straw bales since quite nasty chemicals are sprayed on them. Sometimes crops are sprayed just before the harvest with glyphosphate to dry it up.
 
Posts: 163
Location: Western Washington
18
  • Likes 2
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I don't know about extending the season exactly, but this week it snowed a lot here in western Washington, and the hugelbeds (all built in the last year) have been the first to melt. The plants on them look like they're in a greenhouse, they're so fresh and healthy looking. In a way the beds extend my growing season in another way, since they hold so much water in summer that they make it possible for me to garden at a time of the year where I wouldn't be able to in some parts of my property without them.
 
Angelika Maier
pollinator
Posts: 1361
Location: cool climate, Blue Mountains, Australia
16
  • Likes 1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I myself didn't have much luck with huegelbeds, but maybe it was because the soil I had was too poor. It might get warmer because it is composting and this heats up.
It depends as well what you mean with a raised bed. some people call a raised bed if they raise the soil very slightly over the height of the paths and others take these metal tubs and fill it with soil, both are raised beds but I think they function very different.
 
Bryant RedHawk
gardener
Posts: 4890
Location: Vilonia, Arkansas - Zone 7B/8A stoney, sandy loam soil pH 6.5
564
books chicken dog duck fish forest garden fungi homestead hugelkultur hunting pig
  • Likes 2
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Good point Angelika, perhaps we need some definition here.

The way I classify garden beds:
Bed = at ground level, with or without a border.
Raised bed = bordered bed that is at least 6" above ground level boards are the usual border but rocks, concrete blocks and other solid, soil holing materials work too.
Hugel = a mound that is filled with rotting wood and compostable materials then covered with a soil mix, it does not meet the raised bed definition since it has no border and is not level at the planting surface.

Any time you use a container with a bottom, it is a container planting not a raised bed, raised beds are open to the soil below.

some exceptions, which are actually more like situational adjustments: Wire mesh cover between the ground level and the fill of the raised bed for controlling moles, voles and other burrowing critters.
fabric cover used for the same sort of purpose as wire mesh.
 
Chris Kott
pollinator
Posts: 1820
Location: Toronto, Ontario
125
bee forest garden fungi hugelkultur cooking rabbit trees urban wofati
  • Likes 2
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Well by that definition, kola Redhawk, I guess mine was a bit of a frankenhugelbeet. I used hugelkultur, lasagna-gardening, and a really aggressive barrier mulching strategy, and I hemmed it all in with pallets wired together into a rectangle.

I suppose mine wasn't the best simple example of the potential for raised beds, although I think a lot of people, even on this site, who have read up on the various methods used, will come up with some combination strategy that best suits their wants, available resources, and their understanding of how best to use what they have to improve their conditions.

I think raised beds can be complicated in a variety of ways, but there are many different ways you can customise their design to your specific needs, so that should early and late season extension be a priority, it can be accomplished. It may need more to it than simply piling up dirt in a box open to the soil to satisfy specific requirements, but choosing a raised bed also doesn't obviate any number of options for season manipulation, which might be incorporated.

I think it's a little like choosing the class of your car. Is the type of driving you're going to be doing suited for something with minimal drag that hits high speeds due to a high power-to-weight ratio, sacrificing passenger and cargo space, or do you need a cargo van, or a pickup, or something larger? The raised part might be significant for any number of reasons, but it's hardly the only thing going on when discussing the impact of carefully made garden beds in any configuration.

-CK
 
Bryant RedHawk
gardener
Posts: 4890
Location: Vilonia, Arkansas - Zone 7B/8A stoney, sandy loam soil pH 6.5
564
books chicken dog duck fish forest garden fungi homestead hugelkultur hunting pig
  • Likes 1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
That sounds really cool Chris.

I believe that the best garden beds are those designed to work the way you want them to work for you.
I know a couple who use horse water troughs that they punch holes in the bottoms, add a bunch of punky wood then fill up with their own "potting soil mix", they grow super veggies.
The husband is in a wheel chair and their beds are set up so he can not only work in them but also harvest the produce.
It works super for them and they add a few more every year and they don't plan on stopping until they have the garden of their dreams.

We were talking about gardening and soil and farming one evening and he said his garden was eclectic.
I said it was perfect for his wants, needs and desires so what if it is diverse, nature only thrives because of diversity.
His wife told me that they had been hesitant to tell me about their gardens. I suppose they thought their garden wasn't as great as it is.

I've been fortunate enough to have lived all over the US and several other countries.
What works best at your house might not be the best solution down the street, or anywhere else on the planet.
What works best at my farm, probably won't be the best for anywhere else, all I can do is describe what I do that works for me and make suggestions on things to tryout to see if they might work for you.

We have to be like water, flow around the obstacle, there really isn't much that is rigid in nature, if we want to be rigid we should expect to be worn down to dust just like a mountain.

Definitions are only there so everyone understands what is being described or talked about.

Redhawk
 
Chris Kott
pollinator
Posts: 1820
Location: Toronto, Ontario
125
bee forest garden fungi hugelkultur cooking rabbit trees urban wofati
  • Likes 1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Oh, totally. I just feel that I need to contextualize if talking about my experiences so others can see where methodology and environments overlap in separate cases.

I think, to answer the OP in another way, that if your bed is raised by a low temperature slow compost, or a hot, constant one a ways beneath it, which will be familiar to many making these beds, that you will experience increased soil temperatures for as long as that lasts.

-CK
 
Angelika Maier
pollinator
Posts: 1361
Location: cool climate, Blue Mountains, Australia
16
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Around here there are lots of raised beds out of metal either custom made or old roofing sheets that's why I asked. Of course they are much colder than the soil!
Timber is often treated with nasties which I would not put in my garden and it is expensive. I often did raised beds just raising the soil surface and later I was filling the pathways in between up with woodchips once time allowed and they were available.Probably that heats too?? So in the end my raised beds were not raised, but the woodchips sink down later (they were about 30 cm high). but I want to trial clover in the future.
 
Lia MacLellan
Posts: 8
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Wow, y'all have made some really good points. I hadn't considered the fact that straw bale beds or hugels would have all that lovely biological activity producing so much heat. Between that and possibly greater sun absorption due to their height(?), I can definitely believe that they'd stay warm longer than the ground around them. I always forget that hugels were originally designed by Sepp as a way to compost tons of wood scraps and create soil--it's practically a Jean Pain compost pile already! No wonder it gets so nice and warm.

The fact about mature plants being more tolerant of cold than younger plants makes sense as well. Besides that, cooler soil might actually help some plants improve their flavor, etc. as the growing season draws to a close. Thanks for the information, you've all been very helpful.
 
Posts: 37
  • Likes 1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
4 seasons book - he talks about a French technique, that I'm trying this year. Tilting beds toward the sun - it seems to extned the season and provide a pretty good boost in soil warmth.
 
Chris Kott
pollinator
Posts: 1820
Location: Toronto, Ontario
125
bee forest garden fungi hugelkultur cooking rabbit trees urban wofati
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
As in, just sloping the soil in the bed so that it's higher on the poleward side, Kelly? That sounds intriguing, and I can think of a few reasons that might work wonders.

-CK
 
Bryant RedHawk
gardener
Posts: 4890
Location: Vilonia, Arkansas - Zone 7B/8A stoney, sandy loam soil pH 6.5
564
books chicken dog duck fish forest garden fungi homestead hugelkultur hunting pig
  • Likes 2
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator

Lia MacLellan wrote:. I always forget that hugels were originally designed by Sepp as a way to compost tons of wood scraps and create soil--it's practically a Jean Pain compost pile already! No wonder it gets so nice and warm.



Since hugel beds can be found in Germany, Austria, and some other European Countries that are well over 200 years old, it seems rather wrong to try and give Sepp credit with the creation of them doesn't it?
 
Posts: 72
Location: SW Washington
4
chicken duck forest garden
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator

Kyrt Ryder wrote:With many vegetables the mature plant is far more tolerant of cold soil than seeds or seedlings.

For example I have had tomato plants survive and continue to ripen their fruit into october with night time lows in the low forties.

Weeks gained from warmer soil in the spring for seeds and seedlings more than offsets any loss in the end of the season with mature plants - in most cases. (Exceptions will exist of course.)



This is a big part of the reason I have raised beds (I also have lots of things growing ground level and in hugels). The other part of this is that in late winter/early spring we are absolutely desperate for fresh vegetables, while at the end of the season, we are inundated to the point of giving much away. I started gardening in Alaska and now in SW Washington and I'd much rather have some earlier spring warm up, even at the expense of earlier fall cool down (which in a 6" tall bed is negligible at best, especially considering the first part of this that Kyrt shared and mine are bordered and terraced stone so do hold some heat). Cold frames definitely make a large difference on either end of the growing season.
I do have another reason for having raised beds in that I have clay soil. Drainage and the like are definitely issues, and that clay (being full of water) stays frozen longer than nice, friable soil. Someday, as our soil improves, it will be less of an issue, as I can already see a huge diffference in the 7 years we've been here adding wood chips and mulch/biomatter, but for now, the beds hold less water, so less ice. Come summer droughts, that actually becomes a negative but I pile on the mulch which helps and am slowly adding hugels, which have the best of both worlds.
 
pollinator
Posts: 275
36
  • Likes 2
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Thank you everyone for your ideas and insights. I'll add a few more:

Isn't it all about ecosystems! A local organic market gardener with permaculture leanings uses mounded dirt beds and told me she plants on the ridges in the spring and fall because our ecosystem is *very* wet in the winter, but plants her summer crops in the gullies between because of our summer drought. I used the locally recommended mounds when I was younger but one year when I was ill, some raspberry canes moved into one of my paths (ie lower level) and it has been one of my most productive patches ever since. Raspberries ripen during our normally drought period, so that fits.

I've been experimenting with African Raised Keyhole (ARK) beds (https://permies.com/t/40/68883/permaculture-projects/keyhole-garden-summer-drought#63637 using punky wood at the base, but I don't feel I've got enough years of experience to suggest they are more than one more tool in our tool-box. Drying out was an issue last summer, but the Daikon radish and cabbage survived the winter so far despite over 220 mm of rain in January and a colder than average winter. Our issue is lack of sunshine!

Snow peas that often over-winter here, were planted at grade last fall and appear completely dead. I will see in another couple of weeks if any put out new leaves. They might well have survived in the ARK bed, but would have been too tall for me to pick without a ladder. I mostly planted them for the good of the soil, so I accept whatever the result is, but that points out another issue with raised beds. I planted pole beans at grade last year, and bush beans in the ARK bed, to get the best of both worlds when it came to harvesting.

I've also had mixed success with row covers. Yes they keep the bed warmer, but that may just encourage the slugs to be more active, so if sun is the limitation, the extra warmth may not translate into enough extra growth to out-grow the slugs.

I totally support the opinions above that suggest people have to try a variety of beds with a variety of plants in their area and evaluate over several years. Visiting local environmentally sound gardeners/farmers who've been operating for at least 5 years, would also help one evaluate options that may have merit. Just be sure you know *exactly* what inputs are being used - many local farmers here irrigate daily from mid-June to mid-Sept to get the results they do. I'm less comfortable with that (we're on a deep well and have no way to stock-pile enough winter water to make a difference - I need more experience with those "dew on rocks" techniques!). Similarly, many use plastic both on top of the soil and as row covers and it lasts only a season or two and is not recyclable. Compared to shipped in food, the trade off may be worth it, but it may still not be as sustainable as building some sort of glassed greenhouse for season extension.

Good luck to all who are working towards finding beds that support your needs, and please, if at first you don't succeed, grow, grow again using a different technique, a different variety, a different location....  and please post your successes as well as your failures so that we all get ideas that may help us.
 
This parrot is no more. It has ceased to be. Now it's a tiny ad:

the permaculture playing cards
richsoil.com/cards


  • Post Reply Bookmark Topic Watch Topic
  • New Topic
Boost this thread!