Season Extension: A Key to Temperate Living and Food Security

Written by Doug Crouch

Planning for year round food supply

One of the most important aspects of temperate living is understanding the length of the growing season and how to maximize it to ensure abundant food and energy supply.  With four true seasons and quite a length difference in between frost dates for differing areas,

Humid Temperate Forest, Treasure Lake, the authors families land

temperate living has its perks and challenges.  And with that you have such a variety of climates like hot and humid summers of Kentucky, USA and the lowlands of central Europe, the maritime influenced mild climates of Northern Europe, the dry temperate regions where snow is the main precipitation, and on and on with variation.  One place I farmed in Argentina had recorded a frost in each month of the year throughout the owners extended time there. Thus it is vital to know when to grow what crops, how to integrate perennial vegetables, grow staples (including meat and dairy for some), and how to store them appropriately. We must apply microclimate strategies and techniques as well as the use of appropriate technology to extend the season in the modern-day.

Canal in Argentinian drylands

Springs in the drylands of Argentina create these green oasis

fall ahrvest from a temperate forest garden in Iowa, USA

Slovakian landscape mosaic of forest and field

author and a cultivated wild paw paw patch on forest edge of a campsite of his families land in Kentucky, USA

Crop Diversity

Not all vegetables are created equally in terms of their tolerance to heat and cold and especially frost.  Most of our modern-day vegetables that we take great pleasure in eating, such as tomatoes, beans, cucumber, and peppers, are all warm season annual crops.  They complete their whole life cycle in just a few months and it is always a race to get them in the ground as soon as possible so we can begin to harvest and store some for the winter as well.  This is because primarily they don’t tolerate frost and do not like cooler soil temperatures. Other crops like carrots, beets, salads, broccoli, and the like are all cool season vegetables and can tolerate some levels of frost and for sure much cooler soil temperatures than the previous list.  Thus in our gardens we need to plan for both and one way to do that is through differing earthworks.

Wild foods and perennial foods are also supplements in the diet and season extension. While garlic is consumed all year round currently, it is really not the best for you and often relies on the global food supply.  However perennial vegetables like Egyptian walking onion and chives help to take the pressure off of always adding garlic to meals.  Also there is the wild garlic, a forest herb in Europe, and ramps, the wild leek of North America to help with time diversity. This takes the pressure off of that particular crop and reduces the broad acre monoculture when such a crop is in high demand.  And if it’s fresh in December through May in the Northern hemisphere, it was shipped from places like New Zealand, Chile, or South Africa.  Furthermore, another great food for survivability is asparagus, a perennial vegetable, because it comes out so early in the spring.  Once it gets established after a few years of growing,  it pumps out heaps of food over the years to come.  A perennial vegetable that we find as a wild weed in Kentucky in the forest is garlic mustard.  While hated by many cause it’s not native, it is also a super early food and can even be made into a zesty pesto.

Thin foliage of asparagus popping out over goats rue as a part of a guild on a swale, Ohio, USA

Earthworks

While I have written articles on both sunken and raised beds, the choice often, especially in the more humid temperate zones is raised beds.  However even in a temperate climate you may wish to go with both allowing space for both earthworks and planting different vegetables in those two earthworks.  Please see the articles more on the pros and cons of each but in general people do go with the raised bed because of its ability to warm up soil temperatures and have better drainage away from high water tables.  This extrusion upward is an increase in edge and does create a microclimate of drier and warmer soils earlier on.  If you are farming on a somewhat bigger scale than a small home garden and don’t have incredibly heavy soils, try some sunken beds as well for that second round of summer plantings of things like basil, zucchini and cucumbers. Moreover, if you live in the dry temperate regions for sure sunken beds will relieve pressure of irrigation. It may set you back a week or two of planting while soil temperatures rise but well worth the conservation of precious water resources and your personal energy.

Microclimate

Finding a south or southwest west-facing wall to grow up against in the Northern Hemisphere can really buy you a couple of weeks of time both at the beginning and end of the frost-free growing season. It has for us at my parents garden (Cincinnati, OH, USA Zone 5-6), which amazingly ripens jalapeño peppers still into November long after everything else has died back because of frost or low soil temperatures.  I have written an article on microclimate as well and suggest looking further into that for more detail. You can see in the picture below the houses’ orientation towards southwest and in the south-eastern corner above the terraces against the wall resides a pepper pumping machine of a garden bed.

garden against bottom right corner of the house, south-south west facing microclimate wall

Furthermore, a fusion between microclimate and appropriate technology is the greenhouse.  While in the old days they were made of glass, these days they are mainly made of plastic.  Despite their poor insulate value, both materials work great for keeping soil temperatures up both in the beds where food is grown and in trays for starting plants.  Thus one great way to extend the season is by growing in a greenhouse plants like tomatoes, which can be started 6-8 weeks before they are to be planted out.  By starting the seeds in small trays or flats, the soil in the small cells is easily warmed to get the seeds to germinate.  These starts are then transplanted to pots where they can grow to be one foot (30 cm) or more.  After a process known as hardening off occurs, the plants in pots can then be put in the ground with a six-week head start essentially.  Make sure you keep an eye on soil temperatures outside, however, because every season, especially these days, is totally different. You may not have had a frost lately but cool, rainy, and windy days can keep the soil temps so low that plants like tomatoes will suffer being outside.

Urban Greens Greenhouse, our propagation center for the urban csa

Appropriate Technology

Again the greenhouse is a great use of resources to extend the season.  By growing food in the beds itself within the structure, we can get not only early tomatoes but also greens long into the cool times of the year.  You can also apply microclimate strategies to the greenhouse by adding thermal mass such as barrels of water painted black, piles of stones, placement of the structure up against a brick wall, or even a rocket mass heater.  The latter would turn the greenhouse also into a winter social space, which can be very uplifting to see the color green when everything else outside is brown and grey.  Another way to keep temps up in the greenhouse, especially in the soil where it is so vital, is through an anaerobic compost pile.  My good buddy and running mate some years back in the Cincinnati Permaculture scene Sam Dunlap had done just exactly that.  First the greenhouse was located on the south side of a brick building and he had the goal of growing passion fruit vines from seed he had brought back from Kenya; a true tropical.  Within this zone 5-6 area he built a frame out of a three by three by two stack of strawbales to begin.  From there he layered huge amounts of biomass with a dense concentration of high nitrogen materials.  Down the road was a sheep farmer that had his sheep in the barn for the winter and was happy to give away the manure for the price of Sam simply loading it up into the back of his pickup truck.  As the material was being added, Sam then wrapped a long coil of black irrigation pipe, which then ran out and was split into a long braid to go under the beds thus transferring the heat there.  The system was made into one big enclosed circle so that an even temperature could be achieved.  He used a water pump to pump the hot water from the constant temperature of the anaerobic pile warming the water inside the pipe through the beds to warm the soil and keep food-producing all winter long.  It was indeed warm enough to keep the tropical passionfruit alive and eventually produced fruit.

Another way to extend the season outside of the greenhouse is by using floating row covers often called in the states by their brand Remay.  They are like mini greenhouses keeping frost out and insulating against the cold in general.  They allow light to come through and build a bit of heat on the inside keeping the soil temperatures a bit higher as well.  They are quite easy to put on and off, which makes them quite valuable in the market gardening scene.  Furthermore, I have also used plastic bottles over individual plants to make a mini greenhouse.  In the old days, the French used to use bell-shaped glass to go over warm season plants to extend the season.  If you don’t have the space for a greenhouse another option is a cold frame, which is essentially a small greenhouse.  I built one out of pallets and greenhouse plastic once but they can also be wood on the sides and glass on the top with hinges so you can simply lift it when working with the trays or plants below.  They can be on the side of the garden for a small greenhouse like usage or put directly on top of the bed again to hold heat and build soil temps.  The size is usually around the length and width of a large window but can be any size you like.

Pallet Cold Frame, Alentejo, Portugal

Storage

Once the food has been grown it is important to store that harvest so ample winter supply is there.  First, the simplest form is simply in the ground.  Many root crops can be stored in the ground for as long as possible.  The Jerusalem artichoke, a perennial vegetable, is a great example of this as you can dig even in frozen ground to pull it out.  It’s a super food and should be grown in every garden when an edge planting can be implemented to accommodate its spreading habits.

The next way to store food is in root cellars that are designed appropriately for cool temperatures, constant air flow, and low humidity.  They store mainly root crops but also can store dairy, squashes, and a diversity of ferments.  Some people store grains there as well as fruits like apples or pears that are keeping varieties.  Even nuts and acorns can be harvested and stored in these really important buildings that were once a staple in the homestead landscape.  By having diversity in the landscape as well as a place to store it, the season is extended and we rely much less on the global food system.

Fermentation helps to do exactly this as well as if you want to eat local vegetables in the winter that are not stored in the root cellar like sweet potatoes, then they should have been fermented or canned.  Ferments require much less energy input and supply much-needed vitamin C in the winter as well.  It’s quite a simple process to combine cabbage, carrots and some herbs chopped, salted and pounded.  Place that in a crock and dip into it often throughout the winter like our ancestors once did.  I refer to sauerkraut in this above example but there is plenty of others from cucumber pickles, to hard cheeses, to beet kvass.

Beyond fermentation there are other forms of preservation that help to ensure year round food supply.  Salting meats, canning tomato sauce, and dehydrating fruits are all viable examples.  Sometimes you need to rely on a solar dehydrator or a rocket stove to make it more sustainable but nonetheless it is possible to take more responsibility of your food input.

Dehydrator slotted into Permaculture Food Forest landscape, coastal Portugal

Conclusion: Social Outreach

Overall the challenges of the temperate climate require hard work at concentrated times of the year and lots of good design to ensure the abundance we are after in Permaculture.  We must plan ahead with short growing seasons and do all we can to bring the diversity into the landscape that brings resilience.  And community, while being quite diligent in your own landscape, it’s important to work with others so that these concentrations of labor at specific times of the year are met with a community led response when appropriate.  Rome wasn’t built in a day, nor by an individual family.  So cooperate not compete so that the interconnectedness of community can flourish landscapes both inner and outwardly.

2013 Permablitz for building swales, Cincinnati, USA

Written by Doug Crouch

Header Art by Karsten Hinrichs