This section is from the book "The Gardener V1", 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.
In your Magazine for April, "Under-Gardener " offers "to lay down a rule " for amateurs to be successful in growing Celery in pots. Would he kindly let me have it, either by letter or in the May number of the Magazine, as I should like to try it? - E.G.V.
It is somewhat difficult to lay down any rule in regard to the cultivation of any plant, when that rule has never been proved. Nevertheless, knowing, as we do, the nature of Celery, and the routine hitherto followed in its successful (as far as success was possible) cultivation, we may presume to be able to lay down a rule which, if followed, will certainly secure success.
I need not waste time in directing how the seed should be sown and the young plants treated, as by the time this appears in print most people will have their plants pricked out. However, I may say here, what should be borne in mind all through, never on any account allow Celery plants to receive a check through drought. It is a ditch plant, and any amount of wholesome (as opposed to stagnant) water will not injure Celery while in a growing state. The want of it will ruin the plants and the prospect of a crop.
Bearing this in mind, I would recommend that, when your plants are fit for transplanting in the trenches, select some fine plants with nice balls, and having - say 6 or 8 inch pots well drained with crocks, and a nice heap of soil, composed of sound loam with a liberal mixture of well-rotted stableyard manure, and a good dash of sharp sand - ready, then pot your plants moderately firm, giving a hearty watering to settle the earth among the roots. Now stand your plants where convenience may dictate, preferring, however, a shady place, so that the sun's rays may not parch the soil and injure the roots in the pots. Give, once or twice a-week, weak doses of liquid manure after the pots have become full of roots, so that they may be kept growing vigorously. Now we all know that the stalks produced in summer are not those which are fit for use. The nice, sweet, crisp stalks are produced inside the summer growths after the earthing-up process takes place. To imitate this earthing-up, take strands of bast and tie the outer stalks, not too tightly, and any time in the month of October remove them to any dark shed, cellar, lumber-room, or any other convenient place, where they will throw up their fine blanched stalks.
October may be considered late for the blanching process to commence; but it should be borne in mind that they will grow later in the season than those exposed to cold rains, etc, which will prove another benefit to the amateur who may not have facilities for forwarding his plants in early spring, and who in consequence loses half the season.
I have not gone into the subject as I might have done, but I believe that the hints I have thrown out will be quite sufficient to guide any one who may be willing to give the system a fair trial, and as every person has different ways of doing the same thing, so every one can adopt the plan most suited to his circumstances. - Under Gardener.