Late Fall to Winter Gardening with protection

[applestar]

We are having a sudden dip down to forecasted 20°F this morning….

My garden has gone down to 19°F and may go down another degree or two by dawn.

I’m watching YouTube videos posted by community garden advisors in Japan — here’s one from Tokyo which is around Washington DC level zone. In this video, he is demonstrating how to protect the correctly grown broad beans from frost/freeze while keeping the temperature low enough that they don’t exceed 4 inches which is ideal for winter hardiness.
1. black plastic mulch, supplemented with rice hulls to protect from freeze/thaw soil heaving (rice hulls are available in bulk free or nearly free there… best source here seems to be brewer’s supply, but vermiculite and maybe perlite? might be substituted)
2. insect mesh low tunnel only for wind break/light frost protection — no need to bury bottom edge under layer of soil
3. in case of heavy frost/freeze, loosely cover directly with floating cover (I suspect this is heavier than the summer weight but lighter than winter fleece — most common weight). Only the corners are pinned down and taller than optimal plants are protected by long (usually 10~12 inch) ground pins pushed next to them to raise up the fabric



I’m studying this method as possibly useful in my area for after the ground thaws — starting in early March, and starting broad beans inside, maybe 4~6 weeks ahead, to plant out.

[imafan26]

His garden is so amazing! It is also very big considering how precious land is in Japan. The protection not only protects from frost, but also from the wind.

[applestar]

He is one of “advisors” that work at this particular community / allotment garden.

I haven’t looked at the details enough so I don’t know if it’s a government funded public program — though it seems likely since they post so much detailed information videos — but these gardens are located in various cities (even urban districts in Tokyo) and widely scattered around Japan … and provide on-site guides/advisers who help with tending plants and plots. (Titles of these videos start with “Direct advice from (Japanese) farmers”)

They have supply sheds and facilities for water, compost, all kinds of gardening tools, and parts for support/trellis/protective tunnels, etc. I think they maybe mentioned they sell seeds and started plants to members there, as well as compost, fertilizer (they usually mention composted cow and chicken manures, garden scrap and leaf compost/bokashi), etc., although they take care to generically mention typical sources like dollar stores and big box stores where such supplies can be obtained.

So far, in most of the videos I’ve watched, they operate under organic fertilizer and treatments care regimen, without chemical pesticide, fungicide, etc. (eggshell and grain vinegar, hot pepper and garlic extracts, oil, liquid soap, coffee and potassium bicarbonate, etc.)

At the beginning of the video, the “adviser” introduces themselves with location of the particular garden so it gives me reference for seasonal timing according to their particular climate and zone.

[imafan26]

It sounds much like a community garden program. I'm glad they do have that. We have community gardens sponsored by the city. The wait list on most gardens are in the100's. They do promote organic gardening and the gardeners often use recycled products like egg cartons for starting seeds and compost. They don't have advisors though. It is up to each garden's officers to share information like pest alerts or find speakers for the garden. It is hard to do that because most of the gardens have a diverse community made up largely of immigrants who speak very little English. Even the Filipino community which makes up the largest ethnicity in the garden I used to belong to may not understand each other because they speak different dialects. Speakers are still useful since the majority of the gardeners are second or third generation and can speak English. The ones that don't speak English rarely go to the meetings.

[Gary350]

It is interesting to see how people experiment and learn the best way to grow a garden in their geographical location, their soil & weather conditions. It looks like every plant in his garden is covered with nets, that must be so they don't need to spray for bugs? How do you water plants with plastic ground cover, drip line irrigation? His soil is softer than mine, when our summer rain stops June to Oct our soil is very hard. I see first part of video very windy & gray over cast sky then 2nd 1/2 of video sunny with few clouds & still windy. When we have wind every day soil dries up like desert very quick. Everyone should experiment to learn what works best for them.

[digitS']

The narrow, South bed in the greenhouse was planted to mustard greens, bok choy and leaf lettuce. Surprisingly, the plants didn't burn up in a very warm October. The mustard and bok choy were pulled several weeks ago.

The lettuce refused to grow very much but did make a crop. The roots were left in the ground and we will see if they survive Winter temperatures in there to grow again in February. The heat won't be turned on until mid to late March so they are really on their own.

The middle bench could be removed for a wider bed for Fall transplants but covering during the coldest weather is quite a bother. It is already necessary for some of the potted perennials. That bed can really produce some nice Asian greens by February. Actually, it would make sense to learn if the heavy bench could be left in there. And, see if the angle of the Winter sun is so low that there is no shade from the bench, anyway. I'll try to see if that is true this Winter. The bother of covering/uncovering is one thing but the olde guy needs to think about the weight of a bench made entirely of 2 by 4's .

Steve

[applestar]

I was envisioning tipping the bench over on its side with solid tabletop blocking the north side… if the wood won’t deteriorate from soil contact during the winter.

This way you wouldn’t have to completely lift and remove, nor find a place to store it, and you might use the legs as support for additional protective covering?

[digitS']

As support for the tarps it would make sense, AppleStar. The boards are spaced so it isn't a solid surface.

The greenhouse has a framed and insulated north wall. In fact, the interior paneling is insulated and reflective . It was built with the angle of the south wall allowing the most direct Winter sunlight. Then, I chose not to follow through with container plantings and supplemental lighting and HEAT for Winter growing. I just couldn't justify the expense as a hobby.

Gearing up in March was justifiable . ... Truth be known, my insulated roof begins to cast shade on the edge of the bench by June! And, the sun is high enough by March that light is reflected under the bench rather than on top of it. Oops!

I do have plants under the bench by then, however. There are those perennials even if I don't have a bed of bok choy .

Steve

[applestar]

We are experiencing extreme cold as we usually do around end of December~early January. I’m trying to log as much as possible with my Sunflower Hoop House (SFHH) right now and have been struggling to understand a phenomena where the interior of the SFHH is sometimes colder than the outside —

I finally came across a relevant explanation in a recent Japanese gardening video 放射冷却 (housha reikyaku) = “radiative cooling” *


I’ve also noticed SIGNIFICANT protective improvement after I added different layers for extra protection of the mini napa tunnel inside the SFHH —

In trying to understand the reason for difference, I found this article which provides insight into layers of protective cover materials and their effectiveness —
Sideman RG, A Brown, A Cavanagh, CM Martin and Hazzard R. 2012. .
Temperature Moderating Effects of Low Tunnels Over Winter in Cool Climates

_____
* Here’s a weather report that could be setup with auto translated English cc for reference ~~~

… another video I originally saw explained that one or more opaque protective layers placed over the low tunnels helps to act like the cloud cover to reflect back and keep the radiated warmth from escaping through the clear poly layer (notable that ventilation holes can sometimes actually help to equalize and moderate the extreme temperature loss)

[Gary350]

We are experiencing extreme cold as we usually do around end of December~early January. I’m trying to log as much as possible with my Sunflower Hoop House (SFHH) right now and have been struggling to understand a phenomena where the interior of the SFHH is sometimes colder than the outside —F407F968-F5F0-45D9-A6F6-68B13B8EAF5F.jpeg

I finally came across a relevant explanation in a recent Japanese gardening video 放射冷却 (housha reikyaku) = “radiative cooling”.


I’ve also noticed SIGNIFICANT protective improvement after I added different layers for extra protection of the mini napa tunnel inside the SFHH —EF7A5746-F18B-4A95-BE5F-660F1A629A10.jpeg


In trying to understand the reason for difference, I found this article which provides insight into layers of protective cover materials and their effectiveness —
Sideman RG, A Brown, A Cavanagh, CM Martin and Hazzard R. 2012. .
Temperature Moderating Effects of Low Tunnels Over Winter in Cool Climates

Hysteresis, the phenomenon in which the value of a physical property lags behind changes in the effect causing it.

[digitS']

A different story and anecdotal at that however, last week we had several sunny days but very cold.

Often during the Winter/Spring, the greenhouse temperatures are just a few degrees different from cloudy day, outdoor temperatures.

I checked the thermometers right after noon one sunny day. The outdoor thermometer had just crawled above Zero Fahrenheit. In the unheated greenhouse, it was 53°F . Short hours of daylight and cold!

Now, after a night of darkness, the differences are just a couple of degrees.

In an unheated greenhouse -- 1) If I had a 170 gallon galvanized tank filled with water in there, would there have been a greater temperature difference after hours of darkness, indoors to outdoors? Probably. 2) What if there was very little difference between night and day, outdoor temperatures, much difference? 3) Would 170 gallons of water actually have cooled the greenhouse some on a sunny Winter day? Many observations equals useful information but experience is a dear school .

Steve

[applestar]

There’s a lot to learn, and definitely, it will take a lot of experiencing — by cumulative trial and error — based on local conditions.

That insulation -I do believe- is going to be critical on the much colder days with winter-kill temps, while automatic or manual ventilation to regulate excessively high temperatures (and strategies to avoid the consequent radiative cooling effect without cloud cover causing opposite low extremes) are probably going to be key on warmer and sunny winter days.

…And knowing which winter crops (and which varieties of these …and at what stages of development) are winter-kill hardy at what temperature — I was going to post this link* here as a good example reference, then realized it was among the links I’d already posted on the first page of this thread.

* Winter-Kill Temperatures of Cold-Hardy Vegetables 2018 – Sustainable Market Farming

— reviewed the linked article and realized there have been updates on 2019 and on 2020 —
Winter-Kill Temperatures of Cold-Hardy Vegetables 2020 – Sustainable Market Farming


I enjoyed re-reading the earlier discussions, too — @Digit’S has already been sharing a lot of his extensive experiences

[imafan26]

I learned recently that blowing outside air between a double layered greenhouse sheeting is an insulator. Polysheeting itself is not insulating, but the double sheeting with an air pocket using outside air reduces condensation, better cold/frost protection,
better temperature control.
https://www.bootstrapfarmer.com/blogs/b ... ation-kits

[Gary350]

Summer has returned.

[imafan26]

Your temperature variation is dizzying. Your temperatures are my winter temperatures. I haven't seen a temp less than 61 in years thanks to climate change.