At this time of the year Gardeners are often told dig over your plots now and the icy winter will break down the clumps into a fine fertile tilth. but if its not that cold a winter that wont happen and if it rains a lot you will get sludge next spring so how about trying no Dig.
I admit it, ‘no dig gardening’ sounds a lot like an April fool’s day news skit. But no it really exists and yes it really works. Its origin as a validated organic practice can be traced back to the eminent Japanese microbiologist Masanobu Fukuoka who back in the 1930s developed the philosophy of “Do Nothing Farming”. Very Zen.., but when you consider that it was Fukuoka’s early experiments that later influenced the Australian permaculture and other global organic movements prospering today, then one can appreciate that it is not merely a mediation practice or an intellectual exercise but a genuine viable method of cultivation.
So what is it exactly? Well at its simplest it is ‘above ground gardening’. Effectively gardening into layers of organic and composted material rather than into worked soil. You build up rather than dig down, hence ‘no dig’. Not so strange a leap when you consider that many amateur and professional gardeners grow courgettes and marrows on compost heaps for extra space and extra nutrition for those heavy croppers. Proof in its self that ‘no dig’ cultivation is viable and even bountiful. Proof in its self that it might be worth a shot with other crops. It is so simple and so productive, that once you try it you will be amazed at why it is not the established way of gardening. It is not about making the shovel and spade redundant it is more about making your garden more abundant with less physical effort.
The idea is to not break the soil, which will invariably turn up weed seeds, expose earthworms to the delight of scavenging birds and disturb the work of other beneficial macroorganism and microorganisms all contributing to the soil web and the health of your plot. Instead of digging trenches to add organic matter for improvements to soil structure and fertility the game is to surface dress and let the nutrients leech down, the bacterial activity and the work of worms will loosen the barrier layer between the deeper soil and the organic mulch and then over time will incorporate the two layers into highly cultivatable soil without the flurry of weeds that attends regular soil cultivation and with all of the soil web intact. Genius!
You simply layer enough organic matter on top of the soil that is required for you to plant into. Your potatoes or peonies will start off in the organic layer and extend their roots into the soil below as they mature and the leeching softens the soil barrier. If there is a drawback it is here, some taller plants will need to be staked or supported in the first few years of establishment. If there is a health warning to no dig then it is this – compacted soil will take many years to be amended and ameliorated by no dig methods. That said any other soil type will benefit quickly from do dig, especially poor or tough to work soils.
Good soil is a soil teaming with life. A single teaspoon of garden soil will contain at least a billion bacterial entities. We are conditioned to think of bacteria as the enemy, well yes if on your chopping board but not if in your soil. In fact these soil contained bacterial entities are far from harmful, some of them feed on the excess sugars exudated by the roots of plants thus keeping the rootsphere or rhizosphere, if you prefer, healthy and active, some feed microbes that enable plants to absorb nutrients in the soil, some feed nematodes that act as a defense mechanism to plant roots and to creatures that would harm those roots, the rest are either there to become a natural fertilizer upon decay or as fertilizer spreaders throughout the rhizosphere. Their presence not only improves fertility of soil and plant metabolism but adds to the structure of the soil.
Without bacterial involvement in soil, worms would not be able to function in aerating soil, amongst there many beneficial actions. One of the no dig and organic principles is to let nature do the work; Let the earthworms enrich and ameliorate the soil structure and fertility. In most garden per sq foot (or 0.09square meters in today’s currency), there are in the region of 50 earthworms diligently profiting your soil bank. The aspiration of the organic gardener is to encourage that. No Dig does not disturb the soil ecosystem, no worms get accidentally decapitated, in fact the amount of organic matter that gets introduced via no dig actually boosts earthworm populations and adds more good bacteria to the mix.
The no dig benefit to gardeners beyond the eradication of the traditional backbreaking methods of double digging and endless tilth perfecting is that amazingly less weeds form and also moisture retention is really improved, thereby limiting the two most monotonous of all routine gardening chores immensely, weeding and watering. If you don’t fancy the idea of layering up your garden directly on top of your current soil level then you can make raised beds to place on the surface soil and fill with layers of straw, compost, manure, leaf mould (lasagne-style or compost heap layering if you desire) or you could just fill the boxes with homemade compost. Maintenance is simply to top up beds each year with more compost or organic mulches. It is so simple and so worth the experiment.
The benefit of a raised bed is that combination of free draining soil which is a prerequisite for 99% of vegetables and the extra depth/height ratio which provides extra root room and reliable warmth to the soil. Raised beds warm up quicker in spring and are less prone to frosts as the colder weather progresses thus extending your growing season in two directions, earlier and later. Traditionally for the crop oriented gardener, a raised bed was just good cultural practice for bumper crops and it was no more a process than mounding up. Often just mounding from the excavation of paths or from the formation of demarcation strips around growing zones or particular beds. The problem with this practice is that after a season, (less if a rainy one), the mounds natural subside and occasionally mudslide out onto your paths. So whatever about allotment practices, for the home kitchen garden I recommend that raised beds should be a construction. A boxed off area to cultivate. Boxed by sleepers, planks, recycled bricks, concrete walling, surplus paving, store bought edging; what every your aesthetic or ecological or prudential principles allow or direct you towards.
Raised beds do not have to be the exclusive domain of edible plants. A big attraction for raised beds is their ergonomic value; all those bad-back gardeners can still enjoy the garden by raising it up to a less strainfull level. Veg like a height/depth between 20-40cm But there are no real restrictions, if your back is that bad why not garden at table level. It does not have to be table depth, unless you have the soil to fill it or intend to build up retaining walls as part of overall garden design aesthetics. Gardening can begin at a height, a modified table or a shelving system. The only limit to productivity is your imagination.
I always opt for organic practices as I want my environment and my food to be as chemical free and natural as possible. Organic starts from soil to plant to you. Feed the soil, the soil feeds your crops, your crops feed you. So starting with soil, the no dig method is all about using natural means to feed the soil in the most health effective way, it is about restricting chemical fertilizers, pesticides and herbicides from entering the food web and we will explore that more in a moment but first I would like to look at what frames the raised soil, as it can impact the soil and be a detriment to the food web.
Plastic can leech Bisphenol A (BPA) which can be absorbed by humans via food and contact, with some unsettling health risks from fertility interference to breast cancer. Bpa is the building block of most plastics unavoidable even before we put it in contact with our soil food web. Concrete can over lime a site and cause all sorts of cultivation difficulties. By the laws of deduction one would think ok let’s go with wood. But now the game is truly afoot and we should do a bit of detective work for peace of mind. Around the world, pressure treated or ‘CCA treated’ timber is increasing being banned form use in playground equipment and park furniture. CCA is a concoction of chemicals that have been employed to pressure treat wood since the 1940s.
Ok so naturally chemical treatment and organic practices don’t mix but for most people the reality of life is that its ok to make a small or one time exception to the rule for convenience sake or literally because there is no other way. If your local DIY store or lumber yard only stocks cca wood products then what can you do? Well you can know what cca actually means and leave it in their yard and not have it in yours. CCA stands for ‘chromated copper arsenate’, yes that’s arsenic. And just so you know how potent this stuff actually is; think of a plank of wood, a 12 foot 2×6 plank, the type that you could saw up to make a raised bed, it contains approximately 27 grams of Arsenic…. Scary when you think that that’s enough poison to kill 250 adults. You won’t die to touch it but there is a bit of time bomb situation present, as sawing, burning, reactions with galvanised screws can all cause the arsenic content to be dispersed, as will long time weathering. If local authorities don’t want it for the support structures for swings then I don’t want it near my veg. All that said, don’t panic, there are cca alternatives that are much safer (look for acq instead) and there is the option for untreated wood which is 100% safe bar the splinter or the hammer hurt thumb occasioned from construction and a bit of weathered warp over time.
So to construction. How do you make a wooden raised bed? I am not going to lay out a board-A fits into board-B schematic, you know what they look like and if you need a technical affirmation there are a million you-tube demos out there of how to. If I may I would like to focus on the dynamics of construction. The real trick with a raised bed success story is its dimensions and its contents.
Size matters. Its not that bigger is better, length is entirely what you can accommodate in your garden space, the issue is width. What can you comfortably work across without doing your back in or having to kneel in on to the soil and compact it, crushing some plants in the process. Traditionally width was measured by an arms width in from either side – so you could reach the centre from either side. You can go bespoke to the length of your own arms or follow the now standardised practice of installing a 3 x 6-ft frame. Plenty of space here to take sprawling crops while remaining narrow enough to reach in and harvest or successional plant. Height is to your personal ergonomic preference, standard practice is between 1 to 2ft tall, generally as planks and sleepers fit those dimensions and to be honest if taller then you have to import lots of soil or organic material to fill the volume.
Remember when laying out raised beds, to think of the space between beds, is there enough room to kneel, are you going to be doing a ‘wall of death’ up the sides of your beds with a wheelbarrow or will you have enough room to be comfortably pushing through. The other issue is alignment – in terms of proximity to irrigation systems, a neat 3-5 bed (as to the crop rotation system of your choosing) will make spacing efficient. Are you going to grow grass between the beds to add to your layering or perhaps you like the idea of mulching the paths or setting cobble or slabs. If you decide upon grass then make sure the mower fits, it is one thing to ‘wall of death’ in compost a few times a year but cutting the grass dukes of hazard style on a weekly basis soon loses the ye ha feeling, if not a few toes before that.
Beds marked up, wood frames in place. Now it’s time to make that lasagne. Some people like to add a layer of sharp grit or stones to the base of their beds, many books recommend it, for drainage or weed suppression. You are not planting in a bath tub, so this is not necessary. No matter how wet the summer. Stones only put a barrier layer between grasses and your newly introduced growing media. Grasses that will rot away just as quick with layers of wet newspaper over them. Wet to weigh it down and not blow away when you have gone to fetch the next layer. Stones in soil cause root crops to abandon their straight potential as they fork or spiral out to grow around the obstacle. Keep the stones for your paths or to much perennial beds.
Your next layer can be home compost or even fresh Grass clipping, the sludge that will form for this will keep moisture in the bed a bit longer. Straw is good too. Next if you can get it, well rotted manure. Well rotted means more than a year old, as fresher than that can scorch the plant roots as it breaks down with great heat. A layer of real soil is good at this point. Followed by some organic feed, wood ash, leaf mould to follow. More real soil, homemade compost and so on in any order , until filled. Chicken manure, dried out comfrey leaves, the sludge from your nettle tea, it is all good.
It is not a strict recipe. But I like to recommend that you leave a layer of real soil for the last layer. Real soil is weighty enough to hold the bed down, to firm plants in and it is better to sow in to. You can top dress with compost later on. At this stage the use of soil means the high potential of a weed explosion from dormant seeds being disturbed and awakened. Later top dressing of organic matter will help suppress those weeds and also retain moisture and insulate the soil. After you remove the initial weeds in the first six months of cultivation of your new raised bed, weeds will not be a too much of an issue as from here on in all added layers will be organic matter, weed seed free. The new layers will sink over a season so you will be adding to ‘build up’ as well as feed beds. You could mound up double at the start to anticipate fall in height.
This is a fresh enterprise; it needs a bedding in period. I recommend easy crops like salads or leafy veg for the first seasons until the bed becomes established and the earthworms mix up the layers to a firm consistency. This bed will take any crop in year two, but in year one just note that root crops and legumes ( peas and beans) may not perform as well as the traditional garden (in ground). So give the carrots a miss. It is just those first few months. That said you could construct in winter and all would be ok come spring.
No dig involves the idea of mulching and build up. Above ground gardening as opposed to below ground level gardening. 99% of plants love a much. Some just don’t. Onions wont. Tomatoes will prosper with it. No dig is not all about Veg production. Ornamental plants thrive in it too. Be it a raised bed or top dressing your ground, no dig will boost the productivity of your garden.
Lastly we should consider no dig in terms of its ingredients.
Manure is indispensable. Matured is essential. Well rotted manure will introduce micronutrients and a good quantity of nitrogen when you think it through it is the end product of horses and cows that live of hay and grass which is so abundant in nitrogen. A natural cycle. But w-r-m is good for the worms too adding bacteria, moisture and humus to their environment.
Chicken manure is very high in nitrogen, very aromatic too, pelleted as well as fresh. It does not contain as many minerals and other beneficial elements as other farm yard manures but it still packs a punch. And if you keep chickens then a free punch.
Homemade Compost is the way to go. Rich in all the major and minor nutrients.
Commercial compost is currently peat or peat substitute, both of which are low nutritionally and only good to bulk up soil. That said, changes are occurring as brown bin and recycling facilities see potential in supplying a composted product. Just as the mushroom industry did some time back.
Mushroom compost is the by-product of the mushroom industry, it is the spent compost after the mushroom have been harvested off it. Not very nutritional but a good bulker.
Seaweed – too fresh will burn roots. There is debate about whether it should be rinsed before use, with new thinking leaning to the idea that the sea salt in it or more to the point on it, might actually contain a good mineral boon for the garden. Too much and the salinity of soil will impede growing. Proceed seaweed is commercially available and works a treat.
Lime is often added to increase the pH level of your soil to boost soil fertility in traditional cultivation practices. No dig does not strip out fertility so lime is not a vital ingredient. But certainly optional as a layer ingredient at the start of layering.
Its that simple – apologies if a little long winded – but best to cover it all. So maybe a no dig section might be worth an experiment in your garden next year?