A regional herb gardener relates his experience with growing herbs in a greenhouse.
Last fall, I purchased an herb called fo-ti (Polygonum multiflorum) or, in Chinese, he-shou-wu. It is known as the Oriental “elixer of life”. The long description of its medicinal qualities in the catalog was too appealing not to order a plant. It arrived in a 2 1/4-inch pot, a sliver of a plant with two opposite leaves and a tiny emerging tendril on top. I transplanted it into a 4-inch pot, placed it on the greenhouse bench, and thought no more about it until one day it reached out and grabbed me as I was walking down the aisle next to it. I felt like Seymour in Little Shop of Horrors when he first confronted his Space Invader. I suddenly realized that my plant had already outgrown its pot and had sent several vines coursing through its neighbors. I carefully unwrapped all the vines and gathered them up so that I could repot the plant into a gallon pot. This time, I trained the plant up a stake where I could keep a better eye on it. I forgot about it again, but soon it reached out and grabbed me a second time. The vines had reached the top of the stake, fallen over, and then reunited with another emerging vine and spread outward. I grabbed my clippers and made mincemeat cuttings out of a particularly long and tenacious vine.
Even though I’ve been taken over by this alien species, I’m still taken with its appearance and attributes. And now I’m an agent in its dissemination. The cuttings from the wayward vine rooted in no time, and I sold them in 4-inch pots. Another nursery in this area has had fo-ti planted for a couple of years outside along a fence, where it makes an intriguing dense curtain of foliage. Fortunately, the nursery is on an island where the plant cannot escape to nearby Portland.
Other invaders in my greenhouse are of the pesty variety. All year long, I try to keep the greenhouse pest-free with monitoring, timed releases of biological controls, and an occasional spray. I try to inspect every new plant I purchase, looking for whiteflies, aphids, and scale hidden in the foliage before bringing it into the greenhouse for repotting. Soon I’ll be receiving plant shipments from mail-order nurseries. Sometimes my eagerness overrides my caution, and I don’t realize I’m in the greenhouse when I tear open the box to see if I got all the plants I’d ordered and check their size and condition.
Last year, a visiting nurseryman from the East Coast suggested that I also check for pests in the soil and original pots of mail-order plants. I did and along the sides and near the bottom of one of the pots, I found bits of a bluish gray moldlike substance, the telltale sign of root mealybug, a pest that works underground and munches on roots. The other nurseryman had experienced the same problem and told me that only a soil drench of pesticide was effective in getting rid of it. He suggested that I take cuttings from the infected plant, then throw out the rest of it, the soil, and the pot with the garbage so as not to infect my other plants. Now, after a more thorough examination of everything from plant to pot, I have seen all sorts of new invaders—from strange-looking Californian snails and aphids in new colors to diabolical new breeds of slugs.
On the bright side, I have never found any pests in seeds I’ve ordered. For spring seed germination, there are so many new plants and varieties available that I try to find out as much information as possible about the plant before trying to germinate it. Often a seed packet will have helpful hints such as “cover lightly” (which suggests that it needs light to germinate) or the converse, “cover seed” (indicating a dark requirement). Sometimes I find a tray in which a few seeds germinate one day and a few more on the next. In this case, I can expect germination to be ragged and spread out over weeks. Sometimes, I can improve germination by giving the seed a longer dark period: I put the seeds in a medium such as wet sand and place the container in the refrigerator for a few days. The seed takes up water (the first step in germination) in the cool, dark refrigerator. When I bring the seeds to the greenhouse bench, the warmer temperature there speeds up germination and makes it more uniform.
Seeds that require a moist chilling for several months go into either the freezer or the refrigerator. I try to sow them in the greenhouse on cool or cloudy day , as too radical a temperature change from refrigerator to greenhouse can cause a second dormancy in some kinds of plants; then I would have to stratify all over again.
After the seed has taken up water, it begins to convert its stored energy into sugar. This sugar is water soluble and can leak out of the seed during germination. If the seed is wet or the temperature too cold for proper germination, fungi and bacteria can grow and feed on the leaking sugars and eventually destroy the seed. I didn’t learn that lesson until eleven of my thirteen coral bean (Erythrina herbacea) seeds died. I’m a slow learner.
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