Do not over-prepare your soil
A reader recently wrote that she had enjoyed reading my articles about clearing weedy ground without cultivation; how should she insert plants in her new garden?
I have frequently written about ‘slitting small plants in’, ‘making small holes’ or ‘levering up with a fork or spade and tucking under a handful of bulbs - or even a potato’
I felt my response was bound to be too brief to properly answer and for some garden situations would inevitably be wrong! I seem to remember ironically relating how TV personalities inevitably demonstrated planting on a BBC fluffed up soil, gently inserting a plant with a trowel and finishing - as if a pat on the back - with a shake and a ‘good luck son’ celebratory smile.
In real life it isn’t like that. What about severe soil compaction as a result of previous bad management? What about tree roots, rocks and stones …or a natural iron pan or more commonly a pan resulting from previous rotavation or from a former farmer’s plough? Say nothing about builders! What about really rubbish soil?
Where possible it is best to plant in your unadulterated soil rather than in concoctions in specially prepared pockets. Although plants might get away quicker in ameliorated soil their long term progress will usually be better if they are planted in the soil where the roots are to grow. It is particularly relevant with long lived large plants such as trees.
The most diabolical scenario is to plant in a hole of ‘planting’ compost when the surrounding soil is heavy clay. The plants will like the starting conditions but many such composts dry out and fail to rewet naturally. Plant roots fail to penetrate the surrounding heavy soil and any new growth is stunted. It is worse if your garden is poorly drained when the hole can act as sump for surplus water in Winter.
If you feel you really must use fashionable planting compost, work it in to a much larger zone than the mere hole. As a none digger this option is unavailable to me, thank goodness.
|Once the brambles had been cut down and sprayed away geranium rhizomes were slit into place and aquilegia seed was scattered
In a well managed garden your long term methods will care of your soil - long before and after planting. Best to plant into the soil that you have got.
It’s the same with fertiliser. Fertiliser in the planting hole might inhibit plant roots from reaching out to find long term nutrition and worse highly soluble fertiliser wrongly placed might scorch new roots. Often new trees, shrubs or border plants are not really ready for extra nutrients and it might be best to top dress with general fertiliser weeks or months later. That’s if you need any fertiliser at all.
|When I stopped growing vegetables(!) on my undug vegetable garden, I merely raked off the debris and scattered annual seed
A new site might have one of several histories. If it has strong growing healthy vegetation - whether an existing vegetable garden or border, a grass field, a lawn, an area overgrown with perennial weeds and in my case old cemeteries - I would kill all the weeds with glyphosate and not cultivate at all. All my gardens were prepared for planting this way.
In these circumstances I would only make holes or slits to sufficiently - occasionally generously - accommodate the root span. In the case of the lady who inspired this article her large transplants from her old garden hopefully have good root balls and digging her planting hole would inevitably generate sufficient loose soil to ‘tuck’ the plant in.
|My fifteen year old herbaceous border has never been dug. It was planted in glyphosate sprayed lawn and the dead grass was disguised with a mulch
If planting bare rooted trees loose soil will similarly be available and should be ‘shaken down’ to fill all the spaces. In almost all cases of planting a well directed boot will come into the story to firm the soil down.
If a planting hole provides evidence of a hard pan or general compaction it might be worthwhile to use your spade to break up the base of the hole. Many gardeners mistake a merely settled soil for compaction. Do not get carried away when the soil is merely firm.
|The rowan tree sowed itself and the perennials were infiltrated into the rubble when the ground elder had gone
In general insert plants at the previous depth of planting. With herbaceous plants I tend to plant an inch or so lower and with winter tender herbaceous plants such as dahlias I plant somewhat deeper to hopefully enhance hardiness.
It is important not to plant trees below their bark line as for some subjects any buried trunk will eventually kill them. Occasionally with containerised trees from the garden centre it is even necessary to brush away a little surface compost if they have been potted too deeply.
I think you might have guessed by now that my own holes for garden centre containers are just sufficient to fit them. They rock in the wind less that way. Only when the moon is blue do I stake them.
Height of planting
|Planted on a slightly raised bed on my Winter wet soil. Although 99% of the roots are now in the sometimes very wet soil it got a good start.
For very dry sites plant in a depression
I also had intended to talk about difficult sites due to deep compaction. My instincts are usually to ignore most of these problems but concede there are circumstances were digging and even double digging might be worthwhile. Once only and never again!
As to surface compaction I feel it is not only over diagnosed but that it is usually cured by the first Winter’s frost heave together with plant growth and worms.
|In Lyndi's heavy clay field eight foot weeds were repeatedly sprayed from July, clumps of bulbs were 'tucked under' in September and flowered in Spring.
Links to further reading
I have written about planting before. Not only would I encourage my readers to use my search box - I even do so myself - these links will provide further information. I have to warn you there is some repetition
Although gardeners are generally recommended to not plant on wet soil there is a case for the none digger, or gardeners with sandy soil or just the ordinary gardener planting in settled soil to do the opposite! This post says why.
This post covers some of the above advice in more detail and is generally more wide ranging.
|After elimination of vigorous ground elder in Cathi's grass verge by repeated spraying this never cultivated site was very easily planted in the undamaged soil