Sweet peas flourish outdoors in the cool climates of northern New England, along the shore, the mountains, and other favored sections of the country.
Elsewhere, however, sweet pea growing taxes the skill of home gardeners.
It’s a different story, though, with owners of little greenhouses. They have no trouble providing a cool temperature of 50° to 55° Fahrenheit at night, which sweet peas like, and the proper soil and supports for the vines are easily supplied.
This, at least, has been my experience. As an amateur, I’ve grown sweet peas with the greatest satisfaction for many years.
My Greenhouse
My greenhouse is about 18″ feet wide, and the same length. It has three benches and two walks, and its center bench is of the ìground” or “solid” type.
The soil I contained within concrete walls is 12″ to 14″ inches deep; beneath this soil are small stones, brick hats, old masonry, and worn-out soil.
This conglomeration affords sufficient drainage and supports the growing medium at the standard height of greenhouse benches, about 2′ feet and 6″ inches.
Ground Bench
In this ground bench, each winter is grown an 11-foot row (32 vines) of sweet peas along its westerly edge, about 40 snapdragons in its central part, and a row, partly of parsley and partly of chives, along its easterly edge.
Thus the sun shines over the lower plants and reaches the sweet peas, and the utilitarian and the esthetic occupants of the bench seem to dwell in perfect accord.
Before anything is sown or set on the bench, the soil used in the previous season is replaced with fresh soil.
Soil Mixture
The mixture used is one part by volume of soil from our vegetable-cutting garden, one part rotted manure, one part sand, one part compost (leaf mold), and a double handful of 5-10-5 fertilizer to the 60 cubits feet of the mixture, the contents of this bench.
After the new soil is in place, a trench the width of a spade and the full depth of the soil is opened through it, where the sweet peas are to be sown.
In the bottom of this trench, about 3″ inches of manure is placed with 3″ inches of soil over it, and then the two are thoroughly mixed. The soil dug from the trench is now replaced, and the surface of the whole bench is smooth and fine.
Considering The Sequence of Operations
In a small greenhouse, the sequence of operations has to be considered so that the grower may not be in his way. As a result, the snapdragons occupying the center of the bench are the first plants set.
Wire-String Support
This work is done from both walks and is finished before the wire-string support for the sweet pea vines is set up. Reaching through this rigging to set the snaps would be inconvenient and temper-spoiling.
The support upon which I grow my sweet pea vines consists of four horizontal wires. There’s a turnbuckle on each by which it can be stretched taut.
These wires are respectively 4″ inches, 10″ inches, 16″ inches, and 5′ feet 10″ inches above the surface of the bench soil.
Their ends should be fastened to firm supports. In my greenhouse, vertical angle irons are securely fastened at the bottom by a hook bolt to the concrete bench wall, and at the top are bolted to a horizontal angle iron which in turn is fastened to pipe purling, which is part of the support of the greenhouse roof.
The top wire is roved through brass screw eyes in the wooden sash bars of the roof. Brass is less inclined than steel to rust and rot the wood of the sash bars.
Vertical strings are spaced about 4″ inches apart. They are tied with a slip knot to the top wire, given one turn around the 16-inch and 10-inch wires, drawn fairly tight, and tied with a slip knot to the bottom wire.
It is best to tie a few strings near the center first and work toward the ends. This will tend to keep all the strings fairly tight, but it may be found necessary to go back and tighten some of them.
Between crops, the three lower wires and their turnbuckles are unfastened at one end, neatly coiled, and tied to the vertical support at the other end.
The strings, which generally last two seasons, are separated into about four groups after being unfastened from the three lower wires, and the lower half of each group is gathered together, tied in a loose knot, and allowed to hang from the top wire until wanted again.
Early Flowering ‘Sweet Pea’
Most seed catalogs list a class of sweet pea referred to as Early Flowering, and the description generally states that these varieties “are valuable for winter flowering under glass” or that they are “popular as greenhouse subjects,” to quote two.
It is this class which I grow in my greenhouse, and the following six are the varieties I have used of:
- Late Joseph, salmon pink
- Red Man, crimson
- Christmas Triumph, pink and white
- Kate Smith, scarlet
- White Giant, white
- Tahoe, blue
Seed Sowing
Seed is sown about September 25. I believe, in common with many other gardeners, that Spergon is a very valuable agent with which to dust edible peas, determined to try it on sweet peas.
I have done so for the last two seasons and am convinced it is worthwhile assisting germination.
At sowing time, the lowest wire referred to above is put in place to act as a guide, and a drill about 2″ inches deep is opened directly below it.
Sharp sand (i.e., sand with angular grains like builders’ sand, not beach sand) is sprinkled in the bottom of the drill, is moistened slightly, and the seed is sown upon it about one inch apart.
The seed is then covered with more moist sand and protected by a sort of long tent made by dropping a piece of unbleached muslin over the 10-inch wire and placing some small stones along the muslin’s edges so that it will not be blown out of place.
Generally, I sow about five varieties, and a wooden plant label is inserted in the drill’ to mark where the varieties change.
Another label marked with the name of the variety and the date of sowing is placed midway of each variety and faced to be read from the walk.
The “tent” is removed when the seedlings come up, and the remainder of the wire-string support is set up.
It will be noted that the vertical strings are spaced 4 inches apart while the seeds are sown about one inch apart.
While this appears wasteful, all of the seeds do not germinate, and the excess may be used in part to fill in gaps in the row and the remainder discarded. Sweet peas, if carefully removed from the soil, are easily transplanted.
Vines
As the vines grow, they are wound around the strings, and all the tendrils, which, if left on, would wind around and cling tenaciously to the strings, are pinched out or cut off. The vines stay in place well enough without them.
When vines reach the greenhouse roof, which in the relatively small headroom of an amateur’s greenhouse often happens, two vines are selected, about 4′ feet apart, the slip knots at the bottom of their strings are untied, each vine is carefully removed from its string, carried horizontally to the string of the other and twined around it.
The horizontal portions are supported by one or more loops of string tied to the 10-inch or 16-inch wire. This rearrangement permits the vines to continue to increase in length and produce more flowers.
The reason for pinching out the tendrils is now apparent. Most of the vines are thus rearranged.
My sweet peas, sown in late September, generally bloom in late February and through March. They are used as cut flowers.
They are picked frequently, and any seed pods that form are removed as soon as discovered.
Control Aphids
As a rule, the vines are clean. Burning tobacco dust, a usual procedure in greenhouse operations, keeps aphids in check.
Once, I discovered a sort of climbing worm that worked at night, but hand-picking after dark, after spotting the animal with a flashlight, soon- did away with these pests.
All in all, I have found sweet peas a very satisfactory greenhouse crop. In addition to the joy I get growing them from seed to bloom, there is the satisfaction and pleasure of having brought into being beautiful flowers for the home, for friends, and shut-ins.
44659 by Na