Cut flowers in the home greenhouse provide a welcome profusion of winter bloom and a ready source of flowers for indoor bouquets.
The initial outlay for a packet or two of seed is small indeed for the bountiful supply of flowers that can be produced.
Even if bench space is limited, succession plantings in pots will produce an amazing quantity of cut flowers.
Sow Winter Forcing Seeds
A wide selection of plants will bloom during the winter from fail-sown seed, and the snapdragon is a favorite.
Sow snapdragon seed from late August until early October to provide bloom from soon after the first of the year until early summer.
Two words of caution: Only seed that is marked “winter forcing” will give good results, and since the best temperature range for the germination of snapdragon seed is between 50° and 60° degrees Fahrenheit.
The coolest spot available should be chosen for the seed flat. Often the basement of the house serves well until the seed germinates.
Any good seed-sowing method you have found suitable for other fine seeds will produce a good crop of seedlings.
I prefer to mix together garden soil, compost, peat moss, and sand in equal parts. This is then sterilized in a pail which is placed in a 350° degrees Fahrenheit oven for several hours.
Seed Germination
The period after the seed germinates is critical in the plant’s life. Seedlings like good light with temperatures in the low 70° degrees Fahrenheit to produce stocky growth.
If you can’t provide such conditions in early fall, delaying planting for a few weeks may be better. Spindly seedlings don’t make good mature plants.
Protection From Slugs
At this growth stage, seedlings make an ideal salad for slugs, and it can be very discouraging to walk into the greenhouse some morning and find a row of leafless stems.
Slug baits are not always reliable, so place a fence of polyethylene plastic around the seed flat, preventing the slugs from climbing up the sides.
Transplanting Seedlings
Seedlings are transplanted when they have their first true leaves. If a flat is used, set plants with a minimum of an inch spacing in all directions.
Commercial growers favor direct benching of snapdragon seedlings because it reduces labor, but the amateur can often utilize space better by growing the plants in flats for a few weeks.
The use of plant bands can materially reduce the shock of transplanting. When the plants are about 6” inches tall, the grower should decide whether to grow pinched or unpinched plants.
Pinching Process
An unpinched plant will grow one large stalk of bloom. When this is cut, side branches will form below the cut.
The lower the cut is made, the poorer the blooms will be on the side branches and the longer it will take to produce them.
On the other hand, removing the top half inch of the plant —a process called pinching—will force side branches to form relatively quickly.
Five or six blooming stems of good quality will form on each plant. These will bloom several weeks later than the unpinched plants.
The final spacing of pinched plants should be 7” by 8” inches, while unpinched plants may be planted as close as 3” by 6” inches.
It is possible to pinch every other row to get both quality and quantity. Planning space requirements in advance often saves sowing too many seeds.
Planting In Boxes
The plants that occupy a 2-foot square seed flat take up 4 square feet of space after the first transplanting and may require as much as 20 square feet at blooming time.
I have yet to meet a home greenhouse owner who felt his greenhouse bench space was adequate for all the plants he wished to raise.
Even with a sizable two-ten perature greenhouse, I find myself cramped in the growing room.
I have overcome this problem by planting some of my snapdragons and other annuals in boxes that can be moved about.
Grape boxes from the fruit store are ideal as movable benches if the bottoms are strengthened by braces nailed across the midpoint.
A thorough painting with copper naphthenate wood preservatives will make these boxes last for a number of years.
Important Phase of Planting
Proper temperature is another important phase of planning.
Snapdragons and most other annuals commonly grown during the winter require a night temperature range of 45° to 55° degrees Fahrenheit after passing through the seedling stage.
The same annuals outdoors in the summer do not have so critical a temperature requirement because there is more sunlight over a longer period.
The dark days of winter are not too favorable for flower production, although vegetative growth will be relatively rapid.
With night temperatures above 55° degrees Fahrenheit, vegetative growth will be lush, but there will be very few or perhaps no flowers.
Good Soil and Fertilizer
Good soil that contains compost and peat moss will usually supply the plant with sufficient nutrients until it is 10” to 12” inches high.
Then fertilizer should be applied at biweekly intervals. The high-analysis soluble fertilizers are easy to use and more readily assimilated at this year’s season.
However, the nitrogen concentration should be lower than in fertilizers used during the summer, as too much nitrogen promotes vegetative growth at the expense of flower production.
Staking Plants
Staking plants in a bench is easily done by running wires the length of the bench between rows and running string across the wires, forming squares.
As plants grow, additional levels of wire and string are added—three usually being sufficient.
My carelessness in supporting plants is deliberate. I enjoy arranging flowers and find that crooked stems are much more interesting.
44659 by Cornelius Ackerson