When you work at a greenhouse long enough, you get the question “So, what do you do in the winter?” While some greenhouses close for part of the winter, Malmborg’s stays busy year-round. We use our greenhouses in Rogers, MN to produce plants for our garden centers but we also produce young plants, called rooted cutting, for garden centers around the country and we want to give you a peek behind the curtain of our winter activities.
Why rooted cuttings & why MN?
A cutting is a small part of a plant stem, including a couple of leaves, that is removed from a parent plant. Producing plants from cuttings versus from seed has a couple of benefits. First, plants from cuttings are genetically identical to their parent allowing us to grow consistent plants, and, second, these plants are usually of better quality than those grown from seed.
At Malmborg’s, we produce most of our rooted cuttings from January to April; as you know, this is not prime growing weather in Minnesota. During the winter, the sun does provide some heat to our greenhouses during the day, but we need to heat the greenhouses on cloudy days and at night, in our case with natural gas. So why grow in MN during the winter? One of the biggest reasons is bugs or the lack of bugs during the winter. Growers that produce plants in warmer climates need to spend a lot of their time controlling insects that may damage their plants, in MN those bugs are killed off by our winter climate. Another reason is that we can produce most of the plants near where they will be sold, reducing transportation.
Where do cuttings come from?
We receive our cuttings from plant breeders and growers that specialize in producing parent plants and cuttings. They are located in Mexico, Guatemala, Colombia, California, & Kenya. It is important for parent plants to be grown in areas near the equator where light levels are high to produce healthy cuttings that root well.
These cuttings are shipped to our greenhouse wrapped in damp paper towels to keep them from drying out during transport. They also need to be kept cool to prevent the cuttings from starting to decompose but warm enough so that they don’t freeze and damage the plant tissue.
How are cuttings rooted?
When the cuttings arrive at our greenhouse, we immediately place them into a walk-in cooler to preserve them. They are then taken out to the greenhouse to be ‘planted’, which we call sticking. To stick cutting we put the stem end of the cutting ¼” – ½” deep into a plug that made mostly of peat moss. Some varieties need to be dipped in a rooting hormone to help the root more easily.
The plugs, that are in plastic trays, are placed on special rooting tables. These tables are heated from the bottom and have a misting system that keeps the cuttings moist. After 1-2 weeks, the cuttings will start to grow roots and they will be fully rooted in 3-5 weeks.
Once the cuttings are rooted, they can be transplanted into other containers to be grown for our garden centers or packed in boxes to be shipped to other greenhouses for their growing programs. We sell cuttings to other greenhouses through a group of wholesale brokers that provide greenhouse supplies.
Malmborg’s roots about 5 million cuttings of 1,300 different varieties per year. We produce rooted cuttings of ornamental annuals and edible herbs. Other plants like trees, shrubs, perennials, and more can be produced from rooted cutting but the method may differ from that described above.