Fertilizing & soil building in winter

Because tree roots go dormant in winter, and soil bacteria are "most active" at temperatures above 40 deg F, what is happening in the soil during winter? None of the books I'm reading are answering this, and whether there's anything one should do to contribute beneficially. In some climates we must be able to make some progress in the slower season.

Heaps continue to compost over winter, especially where temps are often above freezing. Here it's often in the 20s at night but in the 30s or 40s during the day,

I do know that you shouldn't add anything much warmer than the soil itself (a liquid fertilizer/tea kept in a greenhouse is OK) because it will shock the existing microbiology.

Is there any point in urigating over winter? If not, what to do with all that fertilizer that accumulates? That would be a lot of airtight containers...

Under 8 inches of leaf mulch, couldn't one create an oasis for the soil food web to holiday in?

In most states and countries, it is against the law to fertilize in the winter.

I know in Maine it is from Dec 1st through Mar 15th. When I was in Ireland I know they had a similar law.

It makes sense because if you over apply too much fertilizer, even if it is compost tea, or manure, the inability to absorb that manure into the frozen ground means it is going to be shed right off into the local waterbodies. That does not do anyone any good. It does not help the fields, and it does not help the farmer, and it does not help the waterbodies.

A prudent farmer has an impervious area that is designated for manure storage, or for making compost, and is sized right so that they can get through the winter months without resorting to spreading it on frozen ground.

There's an interesting book that acres USA just published recently called "humusphere" and in it the author (who lives and gardens in Norway) talks broadly about building so organic matter. The most interesting suggestions he put forth were using "green mulch" (basically grass clippings and the like) as mulch during the summer and then covering your beds with a thick layer of green mulch (in this case small tree branches that still have their leaves and longer pieces of grass) before the frosts come in earnest.
Exactly like you surmised, he claims it makes a bit of a refuge for school biota and provides some food through the winter. He also recommended blending up your uncooked kitchen waste with enough water to make a slurry and spreading that over the dormant beds.
It's definitely an interesting read for anyone interested in that sort of thing and it aligns broadly with the most common winter garden advice that I see which is basically to mulch heavily. The major difference is that he advocates using green material as opposed to brown

Fredy Perlman wrote:what is happening in the soil during winter?

Well I think it depends on both the type of soil and also the geographic location. Soils in the deep south may frost but rarely begin to freeze to depths with exposure to extended sub freezing temperatures. Indeed fungal and microbial activity can slow to a snails pace when the soil not only gets cold, but also when growing things go dormant and temporarily halt the process of secreting root exudates made from photosynthesis into the soil that feed the soil microbial life. Other things such as some soil chemistry can keep right on occurring in cold soils, with rainwater moving or even leaching mobile minerals that aren't bound to soil particles or organic matters, and cation exchange still happening such as the calcium and magnesium in a fall liming displacing hydrogen ions on soil colloids during winter.

Travis brings up an excellent point regarding frozen soils. Applying conventional water soluble fertilizers or manures is not a good idea on frozen ground or even unfrozen but saturated soils. I believe that applying water insoluble amendments such as rock dusts can be done as long as the soil is not bare or has been left fallow for the winter so the rock dusts don't wash away with rainwater erosion, and the soil isn't so soggy and soft that heavy machinery applying insoluble amendments will rut and tear up soil aggregate structure.

True, without root exudates the soil economy has little currency. (Yucky metaphor.)

And good point that enrichments applied to saturated or frozen soil are probably wasted and sometimes illegal. Even mycorrhizal inoculant is better used at another time.

Liberating, in a sense. I can turn my soil building attention to composting only...but Sluggoo investigations should similarly wait until spring.

Very good information in this thread. I had no idea fertilizer was illegal in some areas.
Here, we sometimes get 3 or 4 days a year where actual snow falls from the sky, and maybe 1 or 2 of those days where it actually sticks to the ground for a few hours. We do sometimes have sleet storms that leave ice on the ground for a day or two, but most of our frozen precipitation occurs at night and melts when the sun comes up.
Now, I wonder if the 6+ inches of wood chips & shredded leaves will break down any during the winter.
How do the soil microbes & roots work when the weather is so variable that it may be 35° night and 75° in the day, then a couple of days with highs in the 30s-40s, then back up to the 60s, etc? A couple of weeks ago we got that arctic blast that dropped us to lows in the mid-20s for a few nights, but now we're back to having days with highs near 80 and lows in the 50s.
I would assume root systems don't have an "on/off" switch to become active/dormant at will (?), and I don't know how the fungi, bacteria, etc would respond to fluctuations.

Kc Simmons wrote:I would assume root systems don't have an "on/off" switch to become active/dormant at will (?), and I don't know how the fungi, bacteria, etc would respond to fluctuations.

Oh very much so! Temperature is everything.

It is very plant dependent too. Like winter rye, that can tolerate a temperature down to 33 degrees and grow and germinate. It does not even kill the plant when it goes well below that, the plant goes dormant, but it does not die, and stays green, even under snow. The second the soil warms to 33 degrees, the plant begins to grow again. But corn does not do that. It germinates at 55 degrees, but can live if the temp is colder than that, but I frost-killed when that occurs. Peanuts are another whole story, that not only requires ground temps of 60 degrees, it requires them for 110 days, something that we never get here in Maine in natural conditions.

Of course we can manipulate ground temperatures by using plastic to heat the soil and get unconventional crops for the area to grow, or start plants in a greenhouse and transplant outside at a later date, or grow in greenhouses year around.

Plants are VERY sensitive to temperature. There is only 1 degree difference between 32 degrees, and 33 degrees, and yet winter rye knows the difference. This is why farmers here chop their corn in October, then immediately plant winter rye. All winter it s preventing erosion, and soil building with organic matter, and will be turned under in the spring when the temps allow corn to be planted again. In that sense, farmers are building soil all winter, and on a grand scale.

And the manure for the fields, that too is at work in some degree now that I think about it. That is being dumped into massive tanks where the solids are being settled out, and the water keeps the nitrogen from escaping into the air. In the spring, the lagoon is stirred up, the nitrogen goes into the water, and then that compost tea is spread across the fields.

I add organic amendments to the mulch all winter long. I try to get it down before rain is anticipated.

I like dry coffee grounds, kelp puree, alfalfa, and stuff like that.
I scavenge whatever I can.

Not so much soil building as preparing for soil building, but winter is an excellent time to start making your charcoal for next spring's biochar.  It works especially well if you have animals and can add it to their bedding, but if not, it can easily be added to your compost in the early spring.

Trace Oswald wrote:Not so much soil building as preparing for soil building, but winter is an excellent time to start making your charcoal for next spring's biochar.  It works especially well if you have animals and can add it to their bedding, but if not, it can easily be added to your compost in the early spring.

I'm not any kind of biochar expert, but I've been trying different things with the charcoal leftover from when my neighbor burned some brush in his pasture. I put some in the compost pile, some in the keyhole bed compost, and also soaked some in urine before adding it to the deep wood chips mulch I put in the forest/annual gardens this fall. I figured even if it doesn't do a lot of good, it at least won't hurt to have it in there.

[quote=Travis Johnson]Oh very much so! Temperature is everything.[/quote]

Thank you, Travis. That's what I thought about annual/herbaceous roots.

I should have been more specific, but I was wondering more about trees & woody perennials.
For instance, my pecans, some fruit trees, most NFTs, and various shrubs all dropped leaves and went dormant after the big cold front last month, and will most likely stay dormant above the ground until late Feb. But, would the last few weeks of highs in the 50s-70s and lows in the high 30s-50s result in the roots/microbial life waking up and continuing to work as usual? Or do they mirror the aboveground parts of the tree/shrub and generally stay dormant until the typical "wake up" time?

It makes sense for the top half of the tree to stay dormant until the spring arrives & days get longer since it costs a lot of stored energy to push new foliage; just to have it freeze back in a few weeks and the shorter days not allowing enough sunlight to regain what's been spent.
But I would think the roots wouldn't have as much trouble since they aren't necessarily pushing a lot of new growth and, instead, could take advantage of the warm autumn rains to uptake water & nutrients to better prepare for the foliage push next spring.

The Best Way To Build Organic Matter Fast During The Winter

https://www.advancingecoag.com/soil-amendment-program

No, they act pretty instantly I would say.

I say that going by the Sugar Maple. Their best producing days are when it is cold at night, and warm during the day. That cycle really gets them to pump the sap out of them as they waffle back and forth between being dormant (night) and active again. If it is always cold, or always warm, sap season is nowhere near productive.

That may just be the Sugar Maple though. The Yellow Birch pumps out sap constantly, but it is much later in the season, and when it does flow, it REALLY flows constantly.

To what degree does the freeze-thaw cycle work to create space for springtime fertility by breaking down otherwise inert or inorganic material?

I mulch heavily in the fall, and even though the top layer doesn't have much activity (I live in Oklahoma so we freeze and thaw tens of time over the winter months.) things break down rather quickly and thoroughly in the mechanical sense.

Jordan Mathis wrote:To what degree does the freeze-thaw cycle work to create space for springtime fertility by breaking down otherwise inert or inorganic material?

I mulch heavily in the fall, and even though the top layer doesn't have much activity (I live in Oklahoma so we freeze and thaw tens of time over the winter months.) things break down rather quickly and thoroughly in the mechanical sense.

Jordan, Good point.  I use that very thing to break up my charcoal that doesn't get crushed enough by my truck tires.  By spring, the larger blocks break down to some degree.  Since I incorporate biochar into all my compost, as well as broad forking it in at times, I would think the same would happen underground.  

Jordan Mathis wrote:To what degree does the freeze-thaw cycle work to create space for springtime fertility by breaking down otherwise inert or inorganic material?

I mulch heavily in the fall, and even though the top layer doesn't have much activity (I live in Oklahoma so we freeze and thaw tens of time over the winter months.) things break down rather quickly and thoroughly in the mechanical sense.

I have excellent luck using the spent mushroom block material in the winter. The mold infested wood appears to stay fairly active during the nightly freezes and breaks down quickly.

There is a different technique and philosophy being applied by regenerative grazing. You can google Greg Judy to read up on winter stockpile and ‘bale grazing’. My herd is staying in pasture all winter, and I am unrolling round bales for them. The unrolling keeps them moving across the landscape, leaving fertilllity as they move.

Note: in the picture below, a second bale is being unrolled in anticipation of the next two weeks having snow.

Root growth of trees and shrubs does not match the above-ground activity. On the contrary, many Univ.s extension services and good books reveal that tree roots do the major part of their growth and expansion in winter using the reserves from the above-ground parts accumulated in summer/spring.

Soil scientists like Dr. Christine Jones maintain that the vital boost for soil life/ microbial activity are the plant root exudates. Therefore, the best soil building strategy would be to grow plants. The more, the better. When there are more species together /polyculture/, the plants do better. Up to 16 species together were studied, including flowers, etc, that did best, when compared to 8, 4, 2, 1.

Besides the trees/shrubs' roots many crops and herbaceous plants would grow (and/or germinate) at low temperatures like the nitrogen-fixers: peas, broad beans; also: onions, garlic, rye that was pointed above, oat, many bulb flowers, like crocuses, snowdrops, etc. Seeds of others can be put in ground in the fall/winter for stratification.
So, for me the best winter fertilizing & soil building strategy is to plant trees/shrubs/seeds/bulbs.

Soil that is covered with plant residues and/or plants that remain alive all winter will provide the habitat necessary for members of the soil food web to continue to function.  Here in North Dakota, a covering of snow on top of the plant residues and/or living plants will insulate the soil from extremely cold (below 0 F) temperatures and allow soil organisms to continue to work, if only at a slower pace than when the soil is warm.  The increased biological activity also generates some heat (via respiration as in a compost heap) to keep the soil a bit warmer.  If the carbon:nitrogen ratio of the plant residues are low enough (<~20:1) and there is adequate snow cover, even though the soil may freeze, the residues will decompose, sometimes completely, by spring.  Perennial plants and winter annuals (such as winter rye or winter wheat) will be alive and green under the snow all winter.  Some of the brassicas will eventually die in the cold, but not until air temperatures fall below ~10 F and so may be alive a few months longer than frost-sensitive plants.  Keeping the soil covered with living plants and/or their residues at all times will keep the soil food web fed and functioning, even at a slower rate in colder temperatures.

An interesting bit of advice that Gary Zimmer gave me was to mix your desired trace minerals with a bit of compost or manure and spread it in the fall with tour cover crop. His reasoning was that this would allow the cheaper trace mineral sources (like rock dusts) to get into the soil biological cycle over the fall winter and by spring those trace minerals would be in bioavailable forms tied up in soil microbes and cover crop residues, all ready for your crops to access. I'd imagine phosphorus and other immobile macro/micro nutrients could benefit from the same treatment.
Nitrogen and other highly mobile nutrients are best applied when/where needed

Reading everyone's experiences really shows how much one's local eco-system affects what approach works, but it sounds as if there is an approach for each of these locations.

I have a new raised bed that I finished late last spring, grew tomatoes in last summer, but didn't get the tomatoes out early enough to get a cover crop established. We had an unusually wet September, so even areas I did get planted did not survive whatever kept digging them up every night. Sooo... I "planted" some veggie scraps in the raised bed, then covered it with a 1-2 inch layer of Wisteria leaves, then a couple of layers of brown packing paper I had just to help keep the leaves from blowing off (and a few rocks to hold the paper in place!) We've had a warmer than average winter with only a little below freezing weather, but very cloudy, so not much sun. The other day I decided to lift back the paper to see if the leaves looked like they were decomposing at all. I wouldn't say that the top leaves looked much different than 3 months ago, but the worms were having a party. I figure if there were a bunch of worms there, and not in their "tight ball hibernating" posture, they must be building soil, even if it is at a slower rate than in the summer.

As much as I try to make sure there are plants year round, I find it hard to get things started early enough that they don't just get predated by the slugs. When it's warmer the snakes help to keep the slugs in check, but when I opened a small compost lid today, there were at least a dozen slugs chowing down on the veggie scraps in there. So it is all dependent on the climate one is dealing with. If it was freezing weather here, the cold would slow the slugs down, while the days are so dark, but not this year!

I am in central/south New Jersey, and put shredded leaves on my raised beds. I noticed how dry and compact the soil was this summer. The surrounding 7 acres are home to oaks and pine trees. Will using the oak leaves make the beds too acidic?
Trying to establish some small fruit bearing plants, but the sandy loam that is my soil is not so user friendly. What should I do now? Spring?
I love Nicole mentioning mucking out livestock housing! I personally enjoy cleaning their rooms, and leaving clean sheets(bedding, get it?)

Fredy,
Lots of good information here.  I am mostly going to echo what others have already said with one important addition.  Like so many others have said, putting almost any type of vegetable matter on the ground will help your soil slowly over winter.  

Now if you want to take this one step further, I would suggest that you consider making a compost pile to slowly break down over winter.  I don’t expect that you are going to get any great compost out of this come spring time.  Rather, what I would want to encourage would be all the microbes that will flourish in the compost and work their way into the soil. My experience is that soil that hosts a compost heap is magically fertile, even if the compost is only mediocre.  I still make compost heaps, but I don’t care about the actual compost, I am really interested in how the pile can foster the microbes you really want in the soil.  Every fall I always make at least some type of compost pile, even if I just dump some vegetation on the soil and mix it up a bit.  I don’t worry about turning or heating or getting the moisture just right, I just want to get some microbes to grow in the piles and make their way into the soil, mostly through the action of rain water.

Come spring I might use the residual vegetable matter as mulch or use it to start another pile.  The beauty of this system is that it does not have to be perfect, if you build it, they (microbes) will come.

I hope this is helpful,

Eric

Rita Bliden wrote:

Will using the oak leaves make the beds too acidic?

First, lots of useful plants like things at least a little acidic, and reducing the acidity isn't that hard. Second, there are many things that people worry about composting or adding to a bed which I suspect are location specific.
For example, although I agree that using fresh cedar branches in a hugel bed will slow down your growies, if you live in a cedar environment, there will be lots of cedar eating microbes around and using it as mulch on paths will grow weeds just fine. Since Rita describes her area as being rich in oak trees, oak leaf loving microbes are probably being pooped out by worms as fast as she puts down the leaves. However, someone planted a Eucalyptus tree by the house we now own. Its leaves are resistant to decomposing at the best of times, but also it is *not* native to the area, and I am better to run it through the chipper/ shredder and mix it with a bunch of other stuff in the hope that it will gradually decompose (particularly since the stuff in the shredding pile ends up going into the duck house as bedding and from there to a compost pile.) I suspect someone in Australia near a Eucalyptus forest would have a very different experience with its branches and leaves than I do.

Has anyone else experienced the same sort of thing?

I just started gardening in AZ. I'm new to the heat in zone 10. We don't really get a freeze whitch is nice becuase I have grown lettace, beets, radishes, corn and herbs.

My problem is I can't get the right  soil for melons , cucumbers or tomatos to go more then a few on a vine. plus it get 220 degrees in the summer so a lot just dies if not covered. So I have to plant way early in the winter to have melons in the spring.

any advice?

CJ,

Did you mean 120 degrees?

Yeah, I can believe that growing in AZ heat and aridity is quite a challenge.  For starters I will suggest the obvious—get organic matter into your soil somehow.  By the way, what is the soil like?  Is it sandy, rocky?  Is it the dreaded Caliche?  At any rate, organic matter can only do good.

Regarding that dreadful heat, is it possible that you could put up some screen-like material to cast just a little shade and not fry your veggies?  And that lettuce is really a cool weather plant.  Might you try growing it in winter?  My region gets plenty hot, but it is not a desert and I really can’t grow lettuce except for spring and late fall.

Just a couple of suggestions,

Eric

Rita,

I utilize as many Oak leaves as I possibly can.  The acidity they add is truly minimal.  Resistant Permies soil scientist and expert RedHawk did a nice thread about the “acidifying” effects of Oak leaves and even pine needles.  I will just cut to the chase.  Even a whole bunch of pine needles will just barely increase the acidity.

I utilize a LOT of Oak leaves and they add only goodness to the garden soil.

I hope this helps a bit.  If you need any more information I will try to help.

Good Luck,

Eric

Cj I live in N. Ca. zone 9b and we get temp of 100 to 105 in the summer, and it is hard.  I would mulch to help keep the ground temp down a bit and put up some shade cloth up so your plants get morning and mid day sun, but get some protection from the afternoon sun.  It is the most brutal.  Also make sure your are planting seed, or transplants for your zone.  Seed packets are easy just read the info and usually you know if and when you should plant that seed in your area.  Be careful about the seedlings you buy.  I have noticed at a lot of the places, like Walmart, Home Depot and Lowe's  That they often have things for sell that are not going to grow, or at least thrive in our area.  If your new to the gardening game look for a local nursery.  There you will have a better chance of a knowledgeable staff, and plants that are actually meant to grow in your area.  You may spend a bit more, but at least at ours the people are so friendly and helpful it makes a difference, and it's just more fun to garden with a bit of success.   Good luck to you, keep at it, there is something special about eating fruit and veggies you have grown yourself.

Early Girl tomatoes are a favorite of Phoenix growers.

Eric Hanson wrote:Rita,

I utilize as many Oak leaves as I possibly can.  The acidity they add is truly minimal.  Resistant Permies soil scientist and expert RedHawk did a nice thread about the “acidifying” effects of Oak leaves and even pine needles.  I will just cut to the chase.  Even a whole bunch of pine needles will just barely increase the acidity.

I utilize a LOT of Oak leaves and they add only goodness to the garden soil.

I hope this helps a bit.  If you need any more information I will try to help.

Good Luck,

Eric

I thought about using leaves/wood chips as compost - and came up with this thought?
ANY FALLEN leaves or PRUNED branches FROM A TREE must be great to place as MULCH back under that SAME or SAME TYPE tree.
After all the leaves /branches were made by the tree - and surely they have all that whatever goodness in them that made them grow??
Just a thought
Regards
Don

Fredy Perlman wrote:Because tree roots go dormant in winter, and soil bacteria are "most active" at temperatures above 40 deg F, what is happening in the soil during winter? None of the books I'm reading are answering this, and whether there's anything one should do to contribute beneficially. In some climates we must be able to make some progress in the slower season.

Heaps continue to compost over winter, especially where temps are often above freezing. Here it's often in the 20s at night but in the 30s or 40s during the day,

I do know that you shouldn't add anything much warmer than the soil itself (a liquid fertilizer/tea kept in a greenhouse is OK) because it will shock the existing microbiology.

Is there any point in urigating over winter? If not, what to do with all that fertilizer that accumulates? That would be a lot of airtight containers...

Under 8 inches of leaf mulch, couldn't one create an oasis for the soil food web to holiday in?

I would highly recommend the book Hummusphere by Hedwig Pomersche. He's a Norwegian gardener and researcher of natural processes and the book is a great source of northern European sources translated into English. The primary novel suggestions he makes in the book are to use thick layers of fresh tree/bush branches as over winter mulch and the use of shredded and pureed greenery as a soil mulch.  Worth a read, especially for northern gardeners

Donald,

Certainly fallen leaves/prunings can be used under the same tree from which they fell.  But in my experience, a mature oak tree (or Virtually any other tree for that matter) will grow just fine without the compost of their own fallen leaves.  But adding those same leaves to a garden plot that either needs organic matter to loosen the soil (clay) or bulk up the soil (sand) are immensely useful in the garden plot.

Just my thoughts,

Eric

We collect leaves from our woods and make 4ft beds that we cover in cardboard that we get from local stores for free. The cardboard is weighed down with rocks from our fields (we have plenty of that) and the rest is done by rain/snow/sun/wind cycles....We plant directly into that in spring.

yes 120 to 125 it's hot. but love it.

both sandy and rocky. so I did raised gardens and bought soil but that is getting expensive.

I put a shade on the garden in the heat but it didn't work to good. I think I over watered because I didn't want them to dry out.

I did plant lettuce, beets and corn in the winter and it did pretty good. I might have to do early spring and late summer fall gardening.

Eric Hanson wrote:CJ,

Did you mean 120 degrees?

Yeah, I can believe that growing in AZ heat and aridity is quite a challenge.  For starters I will suggest the obvious—get organic matter into your soil somehow.  By the way, what is the soil like?  Is it sandy, rocky?  Is it the dreaded Caliche?  At any rate, organic matter can only do good.

Regarding that dreadful heat, is it possible that you could put up some screen-like material to cast just a little shade and not fry your veggies?  And that lettuce is really a cool weather plant.  Might you try growing it in winter?  My region gets plenty hot, but it is not a desert and I really can’t grow lettuce except for spring and late fall.

Just a couple of suggestions,

Eric

yes I tried a shade clotha nd it worked ok but I think I had the wrong veggies for the season at that point. everthing bolted and didn't get much. I'm still trying to figure out seed timeing. so different from new england. but seems like I will have more growing season just at different times then I'm use too.

Jen Fulkerson wrote:Cj I live in N. Ca. zone 9b and we get temp of 100 to 105 in the summer, and it is hard.  I would mulch to help keep the ground temp down a bit and put up some shade cloth up so your plants get morning and mid day sun, but get some protection from the afternoon sun.  It is the most brutal.  Also make sure your are planting seed, or transplants for your zone.  Seed packets are easy just read the info and usually you know if and when you should plant that seed in your area.  Be careful about the seedlings you buy.  I have noticed at a lot of the places, like Walmart, Home Depot and Lowe's  That they often have things for sell that are not going to grow, or at least thrive in our area.  If your new to the gardening game look for a local nursery.  There you will have a better chance of a knowledgeable staff, and plants that are actually meant to grow in your area.  You may spend a bit more, but at least at ours the people are so friendly and helpful it makes a difference, and it's just more fun to garden with a bit of success.   Good luck to you, keep at it, there is something special about eating fruit and veggies you have grown yourself.

I utilize a LOT of Oak leaves and they add only goodness to the garden soil.

Thank you Eric! My goal is to add goodness! Love this.
gratefully,
Rita