Friday 30 November 2012

Using glyphosate (4)

Using glyphosate to eliminate weeds from an overgrown plot before making a new garden

Knapsack sprayer
If you have not been reading my previous posts it may be best to press these links now.

Although I spray with glyphosate all year round provided that the weeds have an active green top, many perennial weeds have died down now and in late November it will be useless to spray. Best to wait until the weeds have made a strong head of growth in late spring. If you have still growing green weeds in a temporary open space it will be alright to spray. Similarly if you want to spray-off an old lawn or rough grass sward to make a new garden feature it can be done anytime. I despair when gardeners strip off old turf and throw it away. Far better to leave  all that wonderful dead root fibre in situ.

Glyphosate maths for dummies
If you are using an amateur product the label will explain clearly how much to use. I find many gardeners when using a commercial formulation are confused because instructions  are expressed in litres/hectare. If like me,you are worried about losing a decimal point in your calculation for a small plot, the maths becomes easy if you remember one litre per hectare converts to one ml. per ten  square meters. In point of fact such information is useless to me. For my own purposes it is the strength of the diluted spray that counts. Almost invariably I dilute commercial product (360 gm/ litre concentrate strength) at a rate of 20ml/litre i.e. 1:50 dilution. I only rarely exceed this. Please note for all pesticides there is a maximum permitted dose per unit area.

The village plot is owned by the village community. It was the site of alms houses demolished thirty years ago
Clearing Seaton Ross village plot
Five years ago the plot was a vigorous stand of ground elder, bindweed, couch and much more. It took a year  for my knap-sack spraying to almost clear the plot, another year to completely eliminate the ground elder. In that first year I sprayed four times.
  • My first spray in May was strength 20ml/litre. Subsequent sprays 15ml/litre.
  • I use my ‘directional’ spraying skills to spray at a fairly low pressure to evenly wet the leaves of the weeds just short of ‘run-off’.
  • In recent years I have come to prefer a cone nozzle (rather than the normal anvil type) on a partially extended lance. I do not walk in straight lines with my spray-head  held rigid. I more ‘duck and weave’ and for example I lowered the spray head almost to the ground to spray in a downward direction under and beyond the perimeter hedge.

Five years ago this hawthorn was being strangled by convolvulus (bindweed) and ground elder. It is now cut twice a year by Peggy (Mrs. Seaton Ross) and has been under-sown with fine fescue grass, also cut twice a year.

  • The village plot area is a fifth of a hectare. It took about an hour for my first spray and I used the contents of a full 15 litre sprayer. It’s a good idea for an inexperienced sprayer to practice at first using pure water!
  • It was nearly three months before I sprayed again. It is essential that regenerating weeds are given time to make some new top. It is useless to zap weed immediately it reappears!
  • As I expected by the time of the second spray there were new perennial weeds that had been shielded from spray by the previous weed canopy.
  • The death of the cover of perennial weeds lets sunshine penetrate to the soil below. This is a great opportunity for many  thousands of weed seeds that lie near the surface to germinate, their enforced dormancy broken. Much of the need  for subsequent spraying is to kill them before they self-seed.
  • In the second year of my program I started to slot-in expendable ornamental plants and scatter seeds in newly clear spaces. My spraying now becomes even more directed, more like the ‘spot spraying’ I do in my cemetery gardens. I do not spray bare soil.
  • By the end of the second season no perennial weeds were left.

These mildew resistant forget-me-nots will be a beautiful blue carpet next March. Early in the  project such plants would have been expendable if ground-elder had appeared in their midst.

An apology…
to those of you who do not use a professional knapsack sprayer. It is quite easy to clear a plot with a just a small hand sprayer. It’s just harder work, takes longer and is less accurate. For years my maintenance spraying in Bolton Percy churchyard was with a hand sprayer. If I felt particularly mean, I even used a recycled domestic sprayer!

2018 update I would not contemplate this now and emphasise buying a quality professional knapsack sprayer is the best investment anyone with a medium size garden can make - so much easier and far more accurate. One like the picture I have added to the top!

Tuesday 27 November 2012

Autumn colour

read left to right
 1). Hydrangea foliage compensates for immature flowers
 2). Yellow wisteria foliage behind an alstroemeria which has flowered for five months
 3). Blueberries deserve a place in the ornamental border
We can use the phrase 'autumn colour' just to refer to the general beauty of the autumn garden. This can be things like autumn berries and flowers, coloured woody stems, frost on trees, herbaceous tops and lawn, silken spider webs glistening in the low sun and so much more.  Alternatively the phrase is used, as here, almost as a technical term and refers to the autumn foliage colour on deciduous and, in a few cases, evergreen plants. This is the beauty of senescence when the last of the leaves’ resources are translocated back into the plant, the leaf-bases dehisce and chemical change in the leaf gives those gorgeous pigments.
  • Good colour is promoted by sunshine and cold autumn nights.  Very intense cold is  not good as it will accelerate the rate of leaf-fall.
  • This has been a particularly good year, perhaps because, after a wet season, the  ground is wet and there has been no premature leaf-fall due to drought.
  • When selecting new plants for a garden, autumn colour is an important consideration.
  • With many shrubs and trees raised from seed, there will be considerable variability in their autumn colour. It is best to buy in autumn when you can inspect them.
  • Some plants hold their autumn colour for weeks, even months. Others are extremely transient and their colour is lost in days. 
1). These dogwoods will have beautiful winter stems
2). Acer griseum
3). Cornus florida alba variegata gives summer variegated foliage, autumn colour and  winter stems
4). Leaves of Itea ‘Henry’s Garnet’ are first to colour up and last to fall

1). Thalictrum ‘Elin’ grows eight foot tall
2).  Cut leaf acer
3). Colour change in hydrangea flower
4).  Miscanthus

1). Geranium macrorrhizum, one of the best herbaceous ground cover plants
2). Fothergilla monticola is now outgrowing the rabbits!
3). Maple in my ‘acid border’
4). Polygonum affine ‘Donald Lowndes’

1). Cut leaf maple
2). Cercidiphyllum pervades the air with an intense candy floss smell!
3). Cut leaf maple
4). Astilbes
5). This vitis produces lots of sour grapes

Saturday 24 November 2012

Bolton Percy churchyard winter wind-down

Six months ago, I made my monthly visit to Bolton Percy and found the churchyard completely transformed! Eighteen very large trees on an adjacent property had been chopped down. Absolutely wonderful, a fifty meter stretch of dense dry shade had disappeared. What an opportunity for new planting - all that sunshine and future moisture. The visual structure of the cemetery was completely changed. I am now quite disorientated on my monthly spray-round.
Over the cemetery fence, the mushroom remains of  a 20 meter high tree

Many gardeners mistakenly imagine that a dehydrated piece of land where old trees have grown, will be impoverished. Not so, and with all that lovely leaf-mould, it has been a great opportunity to introduce new plants. It has been so wet this year that on each visit I have been able to scatter seed and pop in plants. No dig gardeners always rush out to plant in wet weather!
No time to sit and ponder.

Two weeks ago, I took about a dozen divisions of herbaceous perennials and ‘gifts’ of seed heads from my other gardens. This time it was aquilegia, Viola cornuta alba, comellina and nigella. I just scatter the seed rich debris, nothing else.

A fifty year unmarked grave. Someone has been remembered by a newly planted rose
This is the time I use my petrol hedge trimmer to start to chop down, shred and scatter herbaceous tops. I do not cut down until a plant has no beauty left to offer. Seed heads of Sedum spectabilis will remain until March. I realize my shredding technique is unsuitable for most small gardens, but I do recommend the hedge trimmer for cutting back herbaceous perennials. It is both quick and tidy. Gardeners will dispose of the dead tops in their own preferred way. Hopefully it will not be in the green bin!

My only help.
She scratched and weeded 
in the moss all morning!
I was pleased to find very few weeds this time - just a few patches of hairy bittercress, epilobium and annual meadow grass. Now that many plants are dormant and some cut to the ground, I can quickly spray in less accessible places. Within the hour, an acre of garden was glyphosate-weeded.

I have recently stumbled on this lovely post about Bolton Percy village. It also contains mention of my cemetery garden.

Wednesday 21 November 2012

Growing healthy plants

Aster novae-belgii is a martyr to powdery mildew. Why is this one so healthy?
More questions than answers

  • If you make a list of pests that can attack a single plant it will shock you. I have thousands of different plants and have only sprayed four times this year. Is plant health the norm?
  • Why do good growers consistently produce healthy plants, and, let’s face it, some gardens are somewhat disease prone? 
  • Why does spraying against one pest encourage a different one?
  • Why do some gardeners reject safe, synthesized pesticides but are happy to use poisons as long as they are natural?
  • When you have a sick plant why does one expert pontificate about virulent pests and disease when another advisor asks about how it was grown?
  • Could it be that most health problems are disorders not caused by pathogens?
You can almost hear the snail’s rasping radula. My Scarborough Lily is rather tatty.
An evolutionary arms race: coevolution
Pathogens and their hosts have often evolved together. There would seem to be a spectrum of relationships with virulent pathogens at one end and symbiosis at the other.
  • Why are some pathogens specific to a single host? Why does chocolate spot fungus only attack broad beans? Its spores are everywhere. Are other plants resistant?  What’s going on?
  • Is there ever an advantage for a plant in nature to be attacked by a pest? It has been suggested that a plant’s ‘spare’ sugar in an aphid’s honeydew drops to the ground and encourages valuable free-living nitrogen fixing bacteria.
This is the first post in a new series about sick plants
I want to suggest answers to some of the above questions and explore what a gardener can do about plant disorders. He will have in his armoury the following solutions
  • doing nothing at all
  • spraying
  • cultural  control - little tricks and sound growing practice 
  • biological controls - these can either be highly successful or a complete waste of time
  • natural control - giving a nudge to nature’s predators and parasites 
I want to explain how some health problems are multifactorial. How there can be a syndrome of related factors. These include growing conditions, climate, pathogen, age and species of plant. 

An example of cultural control
Most gardeners will be familiar with controlling blackfly on broad bean by pinching out infected shoots. The principle is that if the concentrated infection is removed, then nature’s predators and parasites will keep the other aphids in check. In my own garden I apply this idea to plants such as shrubs and herbaceous perennials: the secateurs are my weapon.

This brassica leaf is badly infected with mealy aphid, but the rest of the cauliflower plant was almost pest free. But look, in cutting out the aphids, I have also inadvertently removed a few swollen honey coloured aphids. They are parasitized by a wasp called aphidius, whose larvae have eaten the aphid’s innards. Nature’s not nice!

And just one answer
The aster in the opening picture is healthy because
  • it’s been wet this year
  • the plant is in an open, sunny position
  • although Aster novae-belgii is susceptible to powdery mildew, this particular variety is more resistant than most

Sunday 18 November 2012

Propagating pelargoniums primitively

I call it primitive propagation when I use no special facilities such as propagating cases and frames to root cuttings. I use no special made-up compost, rooting hormone or sprays. Nor do I prepare cuttings in the conventional way, I rarely remove lower leaves. All I need is pots, multipurpose compost, felco secateurs and space on my unheated  greenhouse floor.

Unprepared cuttings. It will be best to remove flowers
Prepared cutting
The best time to propagate ‘bedding geraniums’ is late August. They have time to make sturdy plants before winter. In practice I wait until after my early September open-day. This does have the advantage that by then, there is no need to use polythene to reduce transpiration of the rootless cuttings.

Cuttings inserted and well watered in.

On this occasion I did remove lower leaves. It won’t improve rooting but old leaves will eventually die. It’s quicker and healthier to remove them now. I deeply insert the cuttings into multi-purpose compost and very thoroughly water them in. It is essential for the rootless cuttings to make capillary contact with the surrounding compost. To make sure, I water them twice. They will not be watered again for another two weeks.  For the record, now in mid November, they have been watered four times. Now it is important to let them get quite dry.

After ten weeks 95% of them have rooted

And why all this bother when I can buy plants cheaply in spring.
  • There is immense satisfaction in propagating your own plants.
  • I can maintain stock of my favourite plants.
  • With some dodgy accounting I can persuade myself it’s economic.
  • Every time you buy new plants there is danger of bringing in pests such as whitefly and red spider mite. Together with brown scale and mealy bug, these are completely banned from my garden and if they come in on new plants, my ruthless method of control is to bin them!

I love to inspect the lovely new white roots

Now that it’s mid November penetrating frost threatens. I over-winter rooted cuttings on a south-facing bedroom windowsill, but that’s another story. I now need to work up sufficient courage to tell Brenda that they need to come in.

Now somewhat scruffy the original bedding remains outside. With luck it will survive until Christmas.

Thursday 15 November 2012

Plant of the week: Mum’s the word

Our hardy pink pom pom chrysanthemum. We do not know its name!

Thirty years ago the dentist’s garden in Bolton Percy had a beautiful bedded display of a lovely pink chrysanthemum. To our horror, in late November they were dumped in a roadside skip. I rescued one plant! We have had it ever since. We call it ‘The Fairy’, but I am sure that’s not it’s correct name. One year we lost it. A friend gave us a new plant back. It’s great to give friends plants. When you lose your own, they return them in diamonds!

Our fairy looks particularly good as a specimen tub-plant. It comes into flower in early August: after autumn frosts, and just a little scruffy now, it is still flowering, well into November. For years I grew it in regular peat compost. Now I fill my tubs with my lovely sandy soil. If I make up new pots with my soil-compost, I add slow release fertilizer. Each succeeding year in the growing season, I top-dress each month with a NPK fertilizer. Chrysanthemums are very hungry plants. My ‘mums’ stand on a sunny terrace and are never staked.
Our chrysanthemum is completely hardy (most ‘chrysanths’ are not) and survived the double winter of 2010. For years I overwintered my tubs in an out-of-the-way outdoor corner. These days I have spare space in my cold greenhouse and I just dump them there! 

For demonstration purposes I have cut back these plants a little early. Cut back chrysanthemums are described as ‘stools’. With less hardy chrysanths, it might be better to delay cutting back until spring as the dead tops give a degree of insulation to the roots below.
Each of my large pots contains as many as five stools. Sometimes a few of these stem-bases fail to sprout in Spring. It is easy to tease apart sprouting plants and evenly redistribute them in the pot. On other occasions I root cuttings of detached strong green shoots to further increase my stock.

Successful overwintering
It is curious that chrysanthemum stools overwinter better in their tubs than they do in the open ground. With most tub-plants when left outdoors, the opposite is true. Plants like agapanthus do not like their root-zones frozen solid. Chrysanthemums overwintered in the ground are susceptible to bad drainage and, in very wet spells, heavy soils can be poorly aerated.

And a churchyard story
I once planted a clump of my chrysanthemum in Bolton Percy churchyard. A foolish thing, on it’s rather heavy soil. The day after I had planted six sturdy plants in full flower, I noticed their number had been reduced to five. I could not quite believe my eyes, everything looked undisturbed. Later, when I emptied the rubbish bin (yes, I do that too), I noticed lovely pink chopped-off flowers. The thief had not covered his traces as well as he thought! In fact, everything was so tidy I imagine ‘he’ could be ‘she’.

 A late-flowering unnamed hardy variety

This pom pom ‘mum’ flowers from mid October.

Tuesday 13 November 2012

Green manure

It is my firm belief that plants are good for the soil. Most of the garden should be a year-round living biomass of vegetation. The place of green manure is to fill temporary bare gaps. These often occur in the winter vegetable garden and green manuring is achieved by broadcasting seed of quick growing plants.

read left to right

Reasons to green manure
  • Organic matter is created by photosynthesizing plants.
  • The action of plant roots enhances soil structure.
  • Plant roots absorb nutrients that otherwise would be leached. Most nutrients are held naturally by the soil, but significantly there is no soil mechanism to hang on to nitrates. Sandy soils may also lose a little potassium. Note that leaching loss is a winter phenomenon. In most of the UK, summer rain will take nutrients deeper but they will not be lost to plant roots that follow them down.
  • Certain plants, classically legumes such as clovers, vetches, lupins and tares, have a symbiotic relationship with nitrogen fixing bacteria. These are present in clearly visible root nodules and are able to capture otherwise unavailable nitrogen gas from the air.  
  • Leaf cover prevents heavy rain ‘slaking down’ exposed surface soil and reduces reduces wind erosion of loosened soil. No dig gardeners do not share this problem!
  • Certain deep rooted plants such as comfrey ‘mine’ nutrients from deep in the soil. Comfrey makes excellent compost and liquid feed. 
  • A dense sowing of green manure will help to suppress weeds. Personally, I have a zero tolerance of seeding weeds and such ground cover would impede my weeding. 

In winter I am relaxed about weed cover but refuse to let weeds seed. This eclectic mix of self sown garden plants is hardly conventional green manure but the variegated clover will earn its keep!

Incorporating green manure into the soil

Some gardeners might have a problem incorporating green manure at the end of it’s season. Not for me as a user of glyphosate. When I anticipate needing space for sowing and planting I glyphosate spray. The tops of the vegetation crumbles and enters the soil. Green manure roots remain and decay in the soil. Undisturbed they will perhaps provide a better starter substrate for new mycorrhizal growth that will support the next crop

Soft vegetation that decays on the surface is better for the soil structure than that composted elsewhere and later returned. No matter, this difference at best is quite small and many gardeners will choose to compost untidy dead green manure!

Gardeners who regularly ‘stir’ there soil oxidise organic matter away.
There is some evidence that soft vegetation rotavated into the ground ‘activates’ soil bacteria, whose ‘second course’ is the permanent soil organic matter we ought to preserve.
Those gardeners who do not use glyphosate might just  cut back the tops of green manure and leave it to lie on the surface to decay. Perhaps hoe lightly in dry weather to detach the plants from their roots. If you are worried about slugs read this
Gardeners with different methods to me might just dig it in!

These vegetables will remain overwinter. They are my favorite green manure! 
Sources of seed.

Most seedsmen supply green manure.  Marshalls are good, but if you have several acres try Boston Seeds.

I always have rocket self-seeding in my veg patch. A conventional green manure, and one that you can eat.

Saturday 10 November 2012

From whistler to whisperer

Whistling tree ducks sometimes waddle into our garden.

The farm field at the bottom of our garden floods to create a natural pond. We call it an ‘up and down pond’ and in some years it dries out completely. Not this year, it’s been full all the time and sometimes it becomes quite extensive as water floods over the grassy field. This is an ideal habitat for the tree ducks that used to escape from next door on an almost daily basis. Unfortunately my neighbour has discovered their means of escape and it is only rarely that they come now.

I do love it when they escape from the next door menagerie. They enter the field rather like naughty schoolboys playing truant. They do everything together, in unison. They walk in step, they stand in the shallow water or on the muddy bank, completely still, both looking exactly in the same direction. They have rather a superior, condescending look. If I approach them, they remain quite still and give me a look of dumb insolence which declares “leave us alone”

Duck facts 
  • Their natural habitat is freshwater lakes and wetlands with plenty of vegetation.
  • Native to many tropical regions, they are shot as game birds in America.
  • They eat seeds and water plants, often feeding at night.
  • Their call is a melodious whistle.
  • They are noisy and gregarious, hanging around in big flocks in the wild.
  • Not true ducks, they are considered a separate tribe in the goose sub-family.

The chicken whisperer
A few miles away, Sue Doherty has a seven acre smallholding. She has recently started to blog about her animals. She tells me I ought to get some chickens to provide ‘living garden architecture’. I sometimes wonder whether I should just make a hole in the fence!

Wednesday 7 November 2012

Autumn Bliss

Raspberries in late summer and autumn.

Raspberry 'Autumn Bliss'

I noticed a few a tints of autumn colour on my raspberry plants. Normally an unnoticed clump three meters long, two thirds of a meter wide, runs alongside the fescue-grass path across from my vegetable garden. Next to a shrubby honeysuckle (Lonicera purpusii), a few irregular asparagus plants and surrounded by self sown parsley and Nemophila ‘Penny Black’, it just merges into the ornamental garden. It does have aggressive spreading suckers. The mower takes care of most of these and the others I routinely yank out.

We don’t get particularly high yields. Every second day I stroll up the path with a small pot and pick thirty or so ripe fruits. That’s sufficient for evening dessert each night for at least 3 months.
  • I can expect fruiting from mid August to mid November.
  • The birds do not to take them.This might be because the fruits are protected by foliage.
  • No staking is required. Although I probably should thin them a little, I don’t! I do restrict them to their designated space.
  • There is no skill to pruning - they are just chopped to the ground in late autumn/winter. That’s just five minutes work with my hedge trimmer.
  • Raspberries grow well if given generous nutrition. If I remember, the whole clump gets a handful of NPK fertilizer in late February or March. Roots are then active, and natural soil nitrate is low at that time.
  • Some winters I mulch the cut back stems with a couple of bags of manure. (If I get there first, free bags of manure are at a village garden gate.) I do get resistance from a certain quarter to carrying manure in the back of the car. Unfortunately the manure also provides me with an unwanted reminder of agricultural weeds.
  • Raspberry plants do not last forever, they eventually accumulate virus disease. My plants are six years old and are still looking good. When I eventually have to replace them (and plant on a new site), I might give new varieties ‘Joan J’ and ‘Polka’ a try.

I have recently read about double-cropping of autumn raspberries to extend their fruiting season.This involves not cutting them back to the ground in autumn, and pruning out old shoots in summer. I will give it a try next year on a portion of my clump.

Autumn colour, Autumn Bliss!

Monday 5 November 2012

An important botanical principle

Named varieties of perennial plants usually do not ‘come true’ from seed.
I am using the genus Dicentra to illustrate the principle of seedling variation.
I will NOT be sowing these seeds!
As holder of the National Dicentra Collection, self-seeding dicentras are quite a problem. It is rather embarrassing when purple ones appear in the middle of a clump of  beautiful pink Dicentra formosa ‘Stuart Boothman’. If I did not pull them out they would take over! In February, Dicentra formosa seedlings germinate like ‘mustard and cress’ in my borders. The  seedlings are all different and are my worst weed! I cut away seed-pods in summer, but always fail to catch them all.
The interesting thing about this process is that some of these unwanted seedlings might grow into very fine plants. They may be even better than their parents and be worthy of growing on as a named variety (correctly called ‘cultivar’). I have often lifted seedlings, potted them up and grown them on. In my collection I have some very fine plants not quite worthy of wider distribution (or is it I prefer to keep them for myself?). All such plants if propagated vegetatively remain identical to their parent. They are described as a clone.

Dicentra formosa ‘Adrian Bloom’, like all dicentra cultivars, does not come true from seed
Seed pods of Dicentra formosa alba ‘Snowdrift’.
Its seedlings will be correctly named Dicentra formosa. If you only keep the white seedlings they are called Dicentra formosa alba. They will never be ‘Snowdrift’.
A plant I have raised from seed myself. When I vegetatively propagate this clone I can legitimately call it Dicentra formosa ‘Roger’s Pink’. 
Vegetative propagation of Dicentra formosa is either by division of the whole plant or by forking out root-like underground rhizomes and in my case potting them up to sell on Open Days. (These rhizomes are NOT root cuttings. I know of no dicentra propagated by true root cuttings. Certainly not Dicentra spectabilis, the wallpaper of this blog!  Eminent horticultural encyclopedias say you can!).

Seed pods of Dicentra macrocapnos. Self-sown seed of this species in the wild gives nearly identical plants. It is not helpful if a seedsman makes up a cultivar name when there is little natural variation.
And what is the significance of this variation to gardeners?
1). Hardy plant seedsmen and plant society seed distribution schemes often  offer seed collected from cultivars which do not come true.
2). Cultivar seed will often give plants unworthy of cultivation.
3). Most cultivars of vegetables and annual flowers offered by the ‘regular’ seed trade do come true from seed. Years of selective breeding has made them so. They will not be as identical as members of a clone. 
nb cultivar names of perennials offered by such seedsman are equally dodgy!
4). F1 hybrids come almost exactly true from seed. If you save F1 hybrid seed yourself, you will usually get very variable and unsuitable plants in the F2 generation.
5). Cultivars of some plants, Helleborus orientalis for example, will give  seed-raised plants similar, yet different, to their parent. Seeds collected from a cultivar such as Helleborus ‘Red Lady’ might be sold as the Red Lady strain. They will not be the clone ‘Red Lady’ but they will be fantastic!

Seed collected from this pink-spotted self sown Helleborus orientalis will germinate to give an attractive variable range of pink-spotted plants!
And what about those lovely black seeds in the picture? 
More myrmecochory!
I was fascinated by the information given in the comments column on my recent cyclamen post. When Sonja Hurst-Baird mentioned that dicentra exhibited myrmecochory, I rushed out and shelled a few pods. I think those white elaiosomes are absolutely beautiful.

Thursday 1 November 2012

Why gardeners dig: 5: to degrade organic matter and thereby release nutrients!

To degrade organic matter and release soil nutrients

Most no-dig gardeners will be horrified at this notion, but I suggest it is an integral part of traditional gardening practice. The only time I have read this view stated directly was in a French gardening book! My french is not good and perhaps I got it wrong! To paraphrase, it said, ‘cultivate to aerate the soil: this will release nutrients from organic matter to make the plants grow’.

The two key elements to this process are generous application of compost and/or manure together with attendant heavy cultivations. Depending on your point of view, this is either a virtuous cycle or a pact with the devil! If you break this pact and fail to add organic matter, soil  becomes severely degraded.

In the forties, Lady Eve Balfour, a founder of the organic movement, despaired of agricultural methods which destroyed soil structure and necessitated irresponsible use of fertilizer.

Chickens provide nitrogen rich droppings
Traditional horticulture has always used manure and compost. The great Victorian gardens used horse manure from the stables. The commoners owned pigs or other animals and the chickens provided nitrogen-rich droppings.The mill worker (if he ever had time to garden)used wool shoddy, perhaps the first ‘slow release’ fertilizer. The 18th century market gardens in the London Lea valley used a plentiful organic supply from London streets! All relied on cultivations to both incorporate organic matter and speed its oxidation.


I’m sure that gardeners don’t say to themselves, “I am digging to speed the breakdown of organic matter to release nutrients to feed my plants.”  Nevertheless, it is what happens when soils are cultivated.

There is a paradox at the heart of gardeners’ use of organic matter. Maintaining high levels of organic matter brings a myriad of improvements to the soil, yet the breakdown of organic matter releases  plant nutrients. No dig gardeners try to have the best of both worlds.

Minimum cultivation leads to high levels of organic matter which degrades more slowly. The slower rate of breakdown, but from a high base level, will ensure that plants do not go short of nutrition.

Farmyard manure
Notes on organic matter
  • One of the advantages of high levels of organic matter is that it holds positively electrically charged ions of nutrients such as potassium, calcium and magnesium on its negative charged surfaces. These are available directly to plants and yet are held tightly enough not to be leached away.
  • Nutrients such as phosphorus, sulphur and, significantly, nitrogen are part of the ‘fabric’ of organic matter and only become available when it is degraded. The bacterial process which releases these negatively charged ions is called mineralisation.
  • The speed of bacterial action is controlled by factors such as aeration and temperature. In warm, well aerated soils the process is rapid and soil nitrate levels rise.
  •  A small proportion of soil organic matter  known as humus can persist in the soil for hundreds of years. Recently discovered glomalin can last for decades. Most composts and manures are destined to degrade within a year or two. 
  • Organic matter does not hold soluble nitrate against leaching. Nor does any other soil mechanism. If nitrate is not absorbed by plants it is likely to be lost to winter leaching.

And what is the nodiggardener’s opinion?

I see a process which can work very well when used by skilled gardeners in their vegetable gardens. I am also concerned to explain the reasons why I think this philosophy is a bad thing and intend to write a supplement to Reasons not to dig: part 3

Related Posts Plugin for WordPress, Blogger...