How we seed and grow plants.

Planning our crops

(what farmers do in the winter, other than create web sites)

Deciding on what to grow for bedding plants and vegetables each year takes some tough choices. Hundreds of new plant and vegetable varieties are introduced each year by dozens of seed companies and breeders. Many of these new introductions are hybrids that are patented by the seed companies. These branded plants offer greater vigor, flower power and disease resistance. Some “new” plants are actually old favorites, rediscovered by the general public and back in fashion. Examples of these heirlooms are Salpiglossis ‘Casino Mix’ and Nicotiana ‘Only the Lonely.’

While deciding on which of these new varieties to grow, we must also remember the old favorites (as well as last year’s new introductions) and try to fit all that we can into our greenhouses. It is a tough job, but we are happy to hunker down with the seed and plant catalogs and highlight, circle, exclaim and order for the new year. The characteristics we look for in our selections are suitability to NH seasons and weather, awards (AAS & Fleuroselect), trials we had in past years, and cool new features such as colors, shapes, sizes and forms. We are also greatly influenced by our customers’ comments and suggestions. Please let us know if you are looking for a particular variety.

Once we have a general wish list for new plants, we sit down in front of the computer and enter the plant information as well as the seeding and growing schedules. We also decide on what types of containers we will offer the plants for sale in, and then we double check to make sure we have enough room in the greenhouses. We order the containers and soil we need for the coming season, we order the plant tags and labels we need and we order the seeds and plants. If all goes well, they arrive in time and we start planting.

Seeds Alive

It always amazes us when a tiny seed smaller than a grain of sand can grow into a six foot monster in two months. This is what happens each time we sow Nicotiana ‘Only the Lonely’. The range of seed sizes, shapes and textures is vast, yet they all contain the initial energy and the genetic program for creating a whole new plant. Knowing that seed is alive, respiring and changing with the environment, we try to keep our seeds calm and relaxed. We store them in a cool, dark spot with water-absorbing crystals to keep the humidity low.

If at all possible, we use new fresh seed, as this is the most reliable. If we cannot find fresh seed for a particular variety, we can test the older seed by placing 30 to 50 seeds in a damp paper towel and checking the germination rate. This is a good way for the home gardener to check seeds from year to year. Most seed packets you buy will have a germination percentage and a date of testing. We seed close to 700 varieties each year. Many of these varieties are seeded in succession, every two or three weeks, to provide a constant supply of young, healthy plants for sale at the farmstand.


Plugs are small plants in cell trays that are ready to transplant into larger containers. At Spring Ledge, we grow hundreds of thousands of seeds in plug trays each year. We use a vacuum seeder to deposit the seeds on top of the plug tray so that each seed aligns with the cell of soil. The vacuum is turned off and the seeds drop into the cells. We grow the plugs under lights for a few weeks, then move them to the seedling house where they receive a different set of treatments (natural light, differing temperatures, increased fertilizer, good bugs).

Once the plants fill out the plug trays, both on top and in their root systems, they are ready for transplanting. They are transferred either into 4-packs, large pots or if they are cut flowers or lettuce for field planting, they are transplanted directly into the field. Since the plants are not separated or teased apart, the root systems stay intact and the shock of transplanting is lessened. The plant grows healthier and stronger which translates into fewer pest problems and a better plant for our customers.

There are many plug growers across the country and in Canada who grow only plugs. When the seed is very expensive or takes months to germinate, we purchase plug trays from these growers. One drawback of buying plugs from other producers is the minimum requirement per variety. We don’t need 1000 ‘Yellow Boy’ marigolds all maturing at one time. Instead, we stagger our own plantings of ‘Yellow Boy’ seed to create a steady supply of healthy plants for our customers. We also cannot be sure of what the plug growers sprayed on their plants before they send them to us. If they used a pesticide that is incompatible with our beneficial insects, then we lose out on that release of good bugs. The pesticides on the plugs we bought in may damage our biological controls.


Some plants are propagated not from seed, but from cuttings of stock plants. These are varieties that are best propagated by taking a stem from the mother plant and rooting that stem to form a new, identical copy of the plant. Reasons for propagating by cuttings are that the variety may not set seed readily, it may be a hybrid, or the seed may just be very difficult to germinate. Spring Ledge buys many of these types of plants from other growers.

We purchase over 200 varieties of liners from growers across the country. Included here are all the geraniums, mums, lantana, marguerite daisies and osteospermum. Liners come to us from growers all around the country, from Washington state to Florida to Loudon, NH, where two of the largest growers in the Northeast grow plants (Pleasant View Gardens and D.S. Cole Growers). We purchase the plants, they arrive by express carrier, air cargo, or customer pick-up, we bring them into our greenhouses, inspect them for signs of bugs or diseases, and transplant them into larger containers.

The reasons we do not grow these liners ourselves are several: one is that we do not have the space or scale to economically keep stock plants over the winter and take cuttings. Another reason is that most of these plant varieties are patented, and only certain growers who have paid licensing fees are allowed to propagate them for sale.

Interesting Tidbits

(about plant breeding, branding and the horticulture industry)

Horticulture is using branding to promote and sell highly developed plant material. The appeal of Coca-Cola may lie it its image and brand name along with its consistency. The plant industry is using branding strategies to advertise and sell the newly developed hybrids. Once a seed company develops several outstanding varieties, they may choose to give them a common brand name (“Proven Winners“, “Flowerfields“, “Bressingham Hybrids”, “Garden Leaders”). Branding allows the consumer to know that a plant variety with a given brand name promises high quality growth, flowering and hybrid vigor.

Plant breeding has progressed so that over 10,000 patents are issued to specific plant varieties. It is illegal for a grower to propagate these varieties without a license. Spring Ledge Farm offers many of the new varieties. Licensed growers from around the country ship them to us. Royalty fees paid by us go towards national advertising, promotion and R&D by the breeding companies.

Much of the stock material for the new varieties comes from Australia, South Africa and the Mediterranean region. The plant companies breed these plants with other common annuals. Once the desired attributes are bred into the variety, the company may propagate the plants using virus culture indexing and tissue culture to provide disease free material for growers.

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