Monday, May 16, 2011
Posted by Kate at 10:46 AM
Just a quick report on a successful experiment started early this year with snow peas (mangetout), one of my favorite vegetables. Peas in general are quite hardy plants. They even tolerate freezing temperatures, so they can be sown before the last frost of spring. However, there's one little catch to this. The pea seeds must have favorable conditions (meaning above freezing) to germinate. If seeds are placed in the ground and never have suitable moisture and temperature for germination, they'll simply rot. Once they've germinated, the seeds are as resilient to harsh conditions as the plants they will eventually grow into.
The neat trick is that germination can take place indoors. All one needs to do is soak the pea seeds for about six hours in water to cover, and then drain them and wrap them loosely in a damp paper towel. Keep the moist towel with the seeds in a plastic bag with plenty of air in it for 2 to 5 days, checking the seeds daily and rinsing them gently with fresh water. You will see a pale little spur begin to swell under the seed coat. Eventually this spur will break through the surface of the seed as a root, but you don't need or want to wait that long. If the root emerges by more than a millimeter or so, you must handle the germinated seeds very carefully so as not to damage that root. Far better to get them in the ground as soon as you can clearly discern the root forming up under the seed coat.
I planted pre-germinated snow pea seeds in my cold frame on the last day of January this year. This was an audaciously early date. But it worked. The timing was chosen based on when we get ten hours of daylight back at our latitude. (Ten hours of daylight being a critical minimum requirement for plant growth.) I knew that all the growth from seed to emergent seedling would be fueled by the energy stored in the seed itself, not by photosynthesis. Available sunlight during that time wouldn't matter, but our winter temperatures would slow down that phase of growth. By the time the seedlings poked their heads up above the soil sometime in mid-February they'd have sufficient daylight to continue their growth so much as temperatures would allow. Though the cold frame only has about 8 inches of headroom, I figured by the time the snow peas were of a height to make that an issue, it wouldn't be necessary to keep the cover on the cold frame any more. That's exactly how it worked out. The variety I grow, Snow Sweet, doesn't even require trellising, so it's perfectly suited to being started in such a small space.
The picture above is what our snow peas look like today. I got our first small harvest off of them last night, half way through May, roughly 3-4 weeks early for this area. Typically snow peas peter out once the temperatures get too warm. I suspect these plants will continue to produce through June and possibly even into early July, depending on the weather. We're planning to build a small hoop house this year, which will provide more sheltered growing space than our cold frames, and greater temperature gain as well. These advantages should afford us snow peas even earlier in the season. My plan is to sow germinated snow pea seeds progressively through late winter wherever carrots or other crops are removed from the hoop house beds. I think I could eat snow peas every day of the year and not get sick of them. Maybe by this time next year we'll be testing that theory.
If you want to nudge the boundaries of the possible with plants on your own property, you can figure out the daylight calculations for your own latitude here. You'll need a fair degree of precision in your latitude values. You can get that by looking up your address on either google maps, or google earth, by the way.