Saturday, 8 May 2010

Potting Up & Hardening Off

by Sadge, at Firesign Farm
My last post here dealt with starting my own tender vegetable plants inside, from seeds, to set out in the garden when the weather warms up. Those young plants now need another step or two before they're ready to go out in the garden.

The peppers and eggplants are doing fine in their little six-pack cells. If I'd started them in flats, or the tiny little starter sets they sell pre-packaged, they'd need to be moved to separate pots. The reused six-packs are big enough for them. They can stay where they are until the end of May, when it should finally be safe to put them out in the garden. But the tomato and okra plants benefit from potting up - transplanting to a bigger container.

There's a special technique to use with tomato plants, even those you bring home from the local nursery. If you look closely at the lowest part of a tomato plant stem, you might notice little whitish knobs or bumps. If buried in the soil, those knobs will grow into roots - in fact, any part of a tomato stem will sprout roots instead of leaves if buried. More roots on a young plant will make it grow stronger and faster once set out in the garden, meaning an earlier start to eating those fresh tomatoes. Plus, a stronger root system will deliver more water to the developing fruits, making the plants more drought-resistant and lessening the chance of problems caused by uneven uptake of water.

The night before I want to pot up my tomatoes, I make sure they get a good soaking. My potting table is outside. I want to make sure the soil is wet enough to hold together around the roots - exposure to the wind and the sun will be stressful enough on these tender plants. I get everything ready to go before bringing them out - new deeper containers, labeled and ready to go, and wet down the potting soil I'll be using.

The plants are quickly popped out of their cells, and dropped into the new containers. Any leaves now below the top of the container are pinched or twisted off (you don't want to pull them off and risk tearing a strip all the way down the stem). The root ball is lightly packed down into the very bottom, and then more potting soil added above, surrounding the stem, filling the container to the top.

This deeper burying only works on tomatoes - the okra (and peppers, etc. if necessary), when put into bigger containers, are replanted so that the soil level on those stays at the same spot on the stem. The extra soil goes into the bottom of the new container, the roots will then grow down deeper. When it's time to set these plants out in the garden, use the same techniques. Everything gets set in at the same level they are now, except for the tomatoes. For them, I dig the planting hole even deeper and set them way deep into the dirt, so that only the top few leaves are above ground. If the plant has gotten really leggy, I might dig a trench and lay the plant out sideways, curving the very top up and burying the rest. My plants settle in quickly, thriving even in my hot, dry high-desert climate.

There's still one more step plants started inside need before putting out into their permanent places. They need to be hardened off. This means gradually getting them used to the wind and stronger sunlight out in the open, without causing undue stress. The tomatoes I brought back inside under the lights right away. They'll need at least another week or two inside to recover from today, before I start hardening them off.

But the plants that can take our cooler Spring weather - cabbages, kales, broccoli, cauliflower, chard, and calendula - have been spending their days out on the deck. They're now properly hardened off and ready to go out into the garden. To harden off an indoor-started plant, taking a couple of weeks and doing it gradually is key. Start them out in a shady area, protected from the wind, for just a couple of hours, the first couple of days. Keep them well watered too - wind and sunlight are drying, and you don't want to let the plants wilt. Gradually increase the amount of time spent outside, and increase the amount of time they are in full sunlight. Towards the end of the hardening off period, start easing up on the watering too. By the time you set them out in the garden, there should be very little transplant shock. Even store-bought plants will benefit from some hardening off treatment - they're often so over-watered in the store, to keep them looking pretty, that the shock of transplanting to regular soil, out in the wind, can set your harvest back weeks. And we all want to get started on those fresh-picked veggies as soon as we can, don't we?