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Dirty Fingernails: House plants like their water warm
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Dirty Fingernails: House plants like their water warm

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Q: I read that I should never water my house plants with cold water. Is that true?

A: Cold tap water will not kill your house plants, but they will not enjoy it any more than you would enjoy a cold shower on a February morning. The roots will contract and close their open pores, as will any part of the plant which you sprayed with cold water. The plants will recover, warm up, and open their breathing mechanisms again, but you will have administered a shock.

If you want to be kind to your house plants, you can avoid inflicting a cold treatment on them. The easy way is to fill the watering can as soon as you empty it. Store it full of cold water, which will soon warm to room temperature. Another way to avoid the problem is to feel the water stream going into the watering can. If your finger is comfortable in the water, your plant will be also.


If any of your house plants ever have suffered an attack of aphids, garden writer Greg Coppa says that he has discovered an infallible way of eliminating aphids on indoor plants. The secret is to be ever mindful of the possibility. Notice an aphid outbreak when the bugs are still on flowers and leaf buds. Mix a cup of dishwashing solution, slightly stronger than you would use for washing dishes in the sink. Dip each aphid-encrusted plant tip in the cup and keep it there for a minute. Coppa says the technique has never failed him.

If he does not notice the aphids until they have spread around the plant, he sprays the plant generously with the soap solution. He finds that helpful at controlling numbers but says he never gets rid of all the aphids by spraying them.

Q: How soon can I start planting seeds for this year’s garden?

A: To figure out the first possible date, note on a calendar the last date this spring when you can expect an early morning frost. That date will vary, depending on your altitude, and whether you live in town or the countryside. Your last frost date is likely to be in the last half of May. If you have no idea where in that two-week range your garden lies, be conservative. Assume that you may see an occasional frost until the first of June.

Now look at the information on your seed packets. They are excellent sources. The packet should tell you how many weeks before the last frost date to sow seeds indoors. Times will vary. The slow-growing seeds like Brussels sprouts and petunias can be in little pots already, although they may not yet have pushed up any seed leaves. Other plants (marigolds and cucumbers are among them) will come much later in the season because they sprout within a few days and grow fast.

I do not recommend starting seeds earlier than the package recommends, even when the temptation is great. Roots cramped in small pots when they would like to be spreading in warm soil will not support healthy plants. Instead, they may act as if they had to start growing all over again when they finally move to the garden.

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Every year a few gardeners start an extra-early tomato plant, hoping to earn bragging rights for the earliest ripe tomato. That can be done, but the amount of work involved suggests limiting the experiment to a single plant. For one thing, that tomato will spend weeks in a big pot, one at least the size of a five-gallon bucket. It will have to be hauled to a protected outdoor spot and back into the house every day for weeks.

Most plants will be picture perfect if allowed to grow in sync with the warming weather. They prefer not to be rushed. However, if you are the lucky owner of season extenders — a cold frame, a polytunnel, or walls of water — move your seed planting date backwards four weeks. That is the maximum protected time which a season extender will allow. Plants coordinate their growth with soil temperature and day length as well as air temperature. Season extenders cannot move the sun in the sky.

Q: Last year I started seeds indoors for the first time, and all my plants did not look as good as ones from a commercial greenhouse. Some were smaller, some were tall and skinny, some died. How can I get better results this year?

A: If your plants were small but healthy, and if they grew as well as greenhouse plants, change nothing. Gardeners buying plants tend to reach for the biggest ones. They may not be the best, especially if their roots are crowded or if they are already trying to flower.

Tall, thin plants are suffering from lack of light. If you plan to keep growing plants from seed, you might like to invest in grow lights. This is a fast-changing field now that LED lights exist, and prices are dropping fast. I am amazed by the difference in plants grown under LED lights, as compared to the old-style fluorescent bulbs. They are more shapely, sturdier, larger than any plants I used to grow under lights. It is no wonder that there are windowless warehouses filled with vegetables growing for retail sale.

If you depend on windowsills for starting plants, try increasing their light with reflectors. Cover cardboard with aluminum foil or paint a board glossy white. Set the reflector next to the seedlings, on the side farthest from the light. Enough light will bounce off the reflector for the plants to notice.

To keep seedlings healthy, protect them from the fungal diseases which are common seedling killers: Use good quality seed starting soil. Keep it damp but not soggy. Once the seeds have sprouted, allow the surface to dry before watering again. If your system permits it, watering from the bottom may avoid puddles.

What cured fungal disease in my seedlings was a small, quiet fan in the area. It runs 24/7, and the slight but constant air movement brought a halt to damping-off disease.

One thing to remember if you are new to indoor growing is that plants, like people, need eight hours of darkness at night, so that they can sleep.


An arborist who has worked with the owners of Christmas tree farms offers another way to slow the upward growth of a pine. He suggests using the technique used on pines grown for Christmas trees: wait until the first or second week in July, then cut back the leader. He personally likes to cut it to ten inches. The tree will respond by starting many new buds. The next year, choose one shoot to be a leader; either remove the competing leaders or bend them down to make branches. The end result will be a shorter, bushier tree.

Do this pruning only in the first half of July. Cutting too early will create a number of other problems for the tree.


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