This section is from the book "The Gardener V3", by William Thomson. Also available from Amazon: The New Organic Grower: A Master's Manual of Tools and Techniques for the Home and Market Gardener.
Some few months ago "Mr Iggulden" alluded to the kitchen-garden here under my charge, at the same time suggesting that I should describe the system adopted in bringing the soil into a tolerably satisfactory condition. At the outset it will be necessary to state, that for many years past (at least ten) the old garden in question was condemned as worn out and of comparatively little use. The management of the ground during the early portion of that time I cannot say anything about; but for a few years previous to being in my charge, the system of kitchen-gardening adopted was anything but likely to improve an old garden - cropped and undoubtedly heavily manured for many years. It would be unreasonable to say that the crops that were taken from it were good, because they grew worse and worse until it was difficult to produce a Cabbage. If planted, the whole would club before being ready for use, and had to be cleared away. Many attempts had been made to obtain a new garden, but without success. Although late in the season when it passed into my charge, and the time for cropping close at hand, I resolved to try in earnest to see what could be done towards improving the condemned garden.
However, in the first season but little was accomplished, owing to the large quantity of work remaining to be done, both under glass and in the outdoor departments. The little that was done was done well; and during the summer season preparation was made as opportunity offered to make a good start in early autumn. But, the greater portion of the garden was dug and cropped only to disappoint and annoy; for all the Brassica tribe clubbed and went off as on previous occasions, except a good batch of Brussels Sprouts that was planted upon the ground prepared as the whole garden was intended to be done. The Sprouts were really grand, and gave good hope of improving the ground if the plan started was well and thoroughly carried out, - not one clubbed.
The portion on which they were planted was considered the worst in the garden, but fortunately it turned out to be the best, with a little extra labour the first season. Heavily manuring an old garden that has become impoverished or worn out does not mend the evil, and is, comparatively speaking, of no use. Deep digging cannot be too highly recommended in the improvement of old gardens; but great care is requisite not to bring to the surface too much of the soil that has been undisturbed at the bottom for years, or it will be some time before it is sufficiently fertile to produce a crop, especially if in a sour and unsatisfactory condition, as was the garden here. It had evidently not been disturbed deeper than 8 or 9 inches below the surface for some years. The subsoil was poor hungry-looking stuff to bring up to grow vegetables in, if the ordinary system of trenching had been adopted. In the soil-yard there was found a large heap of old soil that had been used for growing Cucumbers and Melons, and for other purposes, which, when cleared out of the houses, had been allowed to accumulate : this was removed to a piece of ground intended to be operated upon.
In another enclosure were leaves and grass, which had been wheeled from the lawns and allowed to remain for years, and were thoroughly rotted. Quantities of this were carted upon the ground and spread over the surface 6 inches thick, ready when the work of trenching commenced. Only 2 or 3 inches of the bottom-soil were brought to the surface; the leaf-mould and about 2 inches of the surface-soil were placed in the bottom, with some of the fresh soil well worked amongst a portion of the subsoil - in fact, nearly as much care was taken in mixing the whole as if required for potting purposes. The layer of soil near the surface had no vegetable matter, but an extra quantity of the fresh soil incorporated with it. In addition to this, the whole had a dressing of hot lime liberally applied, and only the largest lumps slightly slaked - the rest was turned into the soil without being slaked. It was surprising how it upheaved the soil and quickly made it as light as a bed of ashes, the sodden and sour condition of the soil being soon changed.
Before planting the Sprouts, the ground had to be rolled and made more firm.
The following autumn and winter a good portion of the garden was treated in this way; and from time to time, as quarters became vacant, old potting soil, the surface-soil from Vine and Peach borders, old Vine borders, and all kinds of rubbish from various sources that would burn, was burnt and mixed in as well. All the ground was treated as described, and the lime worked into it in the spring, or sufficiently early to get well cooled before the various crops had to be put in. Knowing that soil of a tenacious nature was much better adapted to the growth of good vegetables, and our soil being light, and made lighter still by the heavy application of lime, clay was obtained and liberally scattered over the surface and allowed to lie through the winter, so that the frost caused it to crumble, in which condition it incorporates with the soil much better than if spread on and dug in at once without exposure to the action of the weather. Clay mixed with the soil remains in lumps unless it be either burned or exposed to frost; and the latter being the best in our case, as the soil was already too light, the clay was dug in at the same time as the lime.
This operation was repeated again the following year, but without the application of lime, when the greater portion of the bottom-soil was brought nearer the top. At this time manure was used for the various crops, but not in large quantities; in some cases it was worked in as the trenching proceeded, in others just before the crops were put in : the latter I think preferable. All old soil is still carefully kept, as it proves of much greater service to old gardens than heavy applications of manure. Fresh soil, clay, and lime are capable of bringing old gardens where the soil is light into a thoroughly satisfactory state; and the latter is, so far as I am able to judge from the effects here, calculated to reduce clubbing to a minimum.
The garden here will now grow all kinds of vegetables well except Carrots, and we hope that they too will soon succeed. It is questionable if ever the ground was in much better condition than it is now; and I do not doubt that it will yet considerably improve, and ere long grow first-class vegetables - as good, at least, as can be produced in this changeable and uncertain climate. These notes on the renovation of an old garden are not intended for those who have had similar circumstances to contend with, and much greater difficulties to surmount, and who have had many years of experience in the renovation of old gardens, and may be able to point out in the 'Gardener' some facts worth recording; but they are intended for those who may be labouring under disadvantages in trying to produce vegetables in exhausted gardens. Doubtless at first the renovation of impoverished gardens entails a large amount of labour - much more so than if trenching, manuring, etc, only were needed. Trenching and thoroughly mixing the soil takes almost double the time of ordinary trenching. Nevertheless it pays well in the end, when satisfactory crops can be produced with some certainty.
When the soil is once got into fair condition, it is not difficult afterwards to maintain it in order, and continue to improve it. Under judicious management it should never require to be all trenched the same season, but a portion at a time, thus extending the operation over a series of seasons. Wm. Bardney.