Coming into April we are preparing for a busy season. The first step is to prepare a seedling nursery, to be seeded down by April 20th. The seedlings grow to about 6″ long in special flats before being mechanically (I hope) transplanted to the field starting around the third week of May.
Given that we live in a northern zone (5a, by the latest reassessment) we need to frost protect our seedlings from day one. Rice growers in cold areas have two main tools for this. The first is water, and the second cover.
The seedling nursery area is relatively small compared to the overall paddy area, maybe around half a percent. So you can raise seedlings in a greenhouse or even a hoophouse or low tunnel. In our case we are using a common Hokkaido method of creating a sort of mini-paddy within the larger paddy. We can then water or even flood the seedlings with the irrigation water already available in the project area.
Rice doesn’t actually need flooded conditions to grow, but it does have high water requirements and doesn’t mind flooding so long as the plants can get enough oxygen. The flooding is often as much for the growers’ convenience as for the plants’ needs. In the nursery period, the young plants can be almost completely immersed in water if very cold conditions threaten. The water provides a thermal buffer, both above and below the surface.
The second, and more modern tool to combat cold is cover. You can use a real greenhouse, or a lower-tech hoophouse or low tunnel. Last year we used a high tunnel, but this year we plan to use a 4′ wide low tunnel, for a total of 300 feet of length. We have a regular high-light-transmission cover to go on it most of the time with a second, heavier, “DEFCON 3” cover to put on if really cold temperatures enter the forecast between April 20th and May 20th.
If there is one thing we’ve learned it’s that the weather is unpredictable. So we take what steps we can, and roll the dice. More soon.