Sprouting Life


It was never my intention to get technical with my blog. But I have to admit that it is awfully hard to talk about reproducing plants from seedlings without getting into complex systems and processes. Nonetheless, for those interested in propagation at Houweling’s, I’m going to try to limit the technical talk and give you a lesson, with a quick and easy Q & A format. I have also included an interesting 60 second video tour conducted by my nephew Ruben, who is Houweling’s Propagation Manager.

Doesn’t every grower propagate?
Ninety-nine percent of tomato, pepper and cucumber growers do not propagate. They buy seedlings from propagation specialists who seed, grade, graft, transplant, stake, clip and ship. Because we insist on controlling and monitoring every step of the growing cycle, we go the extra mile by propagating our own plants in our Delta, BC facility. Like I’ve said so many times before, Mastery under Glass doesn’t come easy.

How do you know which seeds to grow?
We collect data and insight from many sources including consumers, retailers, and seed companies. Then we make the call – the objective being to find the best variety for the season. There are hundreds of seeds to choose from and the role of the propagator (Ruben Houweling) is to study the early growth habits of each combination and then carry out a precise program to create the crop.

Is propagation considered difficult?

Propagation can’t happen without craftsman’s care, systems, machinery, and continued monitoring of temperature and humidity to ensure ultimate growing environments. Before seeding, Ruben studies historical climate data and researches our library of germination data. Seeding requires a vacuum machine that picks 240 individual seeds at once and plants them into a tray prefilled with nutrient-enriched plugs. These trays are sealed to keep moisture in; 3 to 4 days later they are opened to the sunshine to await the very first set of leaves (cotyledons).

How fast do seedlings grow?
Under warm conditions, tomato seedlings grow quickly. Before they become too crowded, a grading machine plucks the plugs from the trays, takes digital pictures, and assigns new trays based on height and leaf surface area. Although there is plenty of automation, the programming necessitates the care of a skilled operator.

How long does it take for a seedling to be ready to ship to the regular greenhouse?
The entire cycle takes 42-56 days. But there is a lot to do before the young plants leave the propagation house. After grading, comes the critical step of grafting which is done by hand with surgical attention. It is very important to fuse a matching size of scion* and rootstock**. Each rootstock and scion is cut at a 45 degree angle with a razor and then held together with a small silicon clip in a high humidity chamber.

So you just wait until the plant is big enough to ship?
Not in a long shot. The vigorous roots of young seedlings quickly outgrow the seed tray. That means transplanting by hand into a larger block (casing) made of mineral wool that is saturated with warm, nutrient-rich water on a conveyor belt. A mobile dispensing machine collects the blocks from the conveyor and moves them to various destinations in the greenhouse for continued growth.

How big is the plant before it is shipped?
At 4” of growth we insert a stake by hand and at 10”, a clip is applied to fasten the stem to the stake to prevent snapping during handling. Six to Eight weeks from seeding and we are ready to ship a 12” plant to our tomato growers.

Although I’m quite sure Ruben will say that I’ve missed a few stages along the way, this should give you a basic idea of how we propagate and why care and attention is so important to develop the perfect plant for the next stage of greenhouse growing.

With my regards,

Glossary of Terms:
*‘Scion’ is the term we apply to all varieties that serve the function of producing fruit but its root system will be cut away and discarded in the grafting process.
**‘Rootstock’ will be the variety that provides the plant a root system only.  The rootstock is chosen for its vigor and disease resistance but not for its fruit characteristics.  

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