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.
Having a small greenhouse and forcing pit, I try to have a bloom all the year round; and to obtain this my attention was called to the Primula. The first time I tried to grow them from seed I was rewarded with good plants; they grew well all summer, but when winter came they got dull-like, and began to damp away, until they all died. I afterwards found out the cause; they had been watered rather too freely. Finding I could not do without the Primula, I tried again, and was successful this time, paying great attention to the watering.
Should any amateur wish to get up a stock of these beautiful inmates of the greenhouse, I venture to note down my experience; it differs a little from what I have read. I buy a packet of good seed, sow about the beginning of May - last year I sowed on the 3d of May - in wide-mouthed pots; for it is better to have a good body of soil under the seed, instead of the reduced quantity contained in seed-pans. For compost I use one half rotten turf, one half sharp sand. Use clean pots; fill nearly half full of drainage, then add the soil; nil to the top, press moderately firm, and then sow the seed thinly and evenly; cover very thinly with fine soil, water with a fine rose, or by drawing the hand across a wet brush, cover with a pane of glass. Then I put them in the forcing-pit; water when the surface gets dry; remove the glass as soon as the seedlings appear; when they have two rough leaves, prick them out an inch apart in a seed-pan, using the same soil as before, adding a little soot and cow-dung mixed well together. They are now put in a warm frame for a month, by which time they will be ready for potting singly in 5-inch pots. I have tried larger and smaller sizes, but they do best in the 5-inch the first year; they may have a larger the second.
For soil for potting I use one-fourth rotten turf, one-fourth horse-droppings, fresh from the stable (it being free from worms and their eggs), and one-half sharp sand. The Primulas delight in open soil, in which their roots can run freely. The pots should be clean, and the drainage also. Till the pot one-fourth with drainage, then add the soil, keeping the plants well up in the pots. After watering well to settle the roots, remove them to the greenhouse,|as near the glass as possible: give plenty of air; water them as they require it while growing. As winter approaches be more careful in watering; water round the edge of the pots. On no account let water fall on the crowns, or they will damp off before you are aware. By the beginning of September they will begin to show flower; pick off the first blooms as they appear. After this they will send up immense trusses of bloom, some three, four, and five at a time; they should have plenty of room for their fine foliage. The blooms of several of mine were as large as a crown-piece; indeed, when the crown-piece was laid on, the fimbriated edge stood out like a frill all round. They are still blooming, and as brisk as ever. The fern-leaved sorts are interesting whether in bloom or not.
I turned some of the plants out of the pot to see what the roots were like. The ball was white with fibre, putting me in mind of white silk-thread. As the soil gets exhausted, they will be the better of a little guano-water. As soon as they are done blooming, about May, shake the old soil from the roots, and repot in the above-mentioned soil. My little greenhouse has been gay with Primulas, Camellias, Bulbs, etc. etc, all winter. My Cinerarias, being late, will come in about the time the Primulas are declining. They were sown the same day as the Primulas. The above treatment suits the Primula well. I will never want it in the greenhouse.
H. T. C.
[We gladly give these simple but sound remarks of an amateur, and hope some of our numerous amateur friends will favour us at times with their experiences, which are sure to be useful to others similarly engaged and situated. - Ed].