While looking through a seed catalog, I came across a plant called calendula or pot mari-gold. Is this plant different from the annual marigolds that I usually buy at garden centers in the spring?
The pot marigold, Calendula officinalis, is different from the African marigold, Tagetes erecta, and the French marigold, Tagetes patula. All three mari-golds are in the aster family; however, as you can see from the Latin names, the pot marigold is in an entirely different genus from the other two.
From a distance, the pot marigold may be confused with the African and French mari-golds because their flowers have similar, shape, texture and color. However, the foliage is distinctly different. The pot mari-gold comes from the Mediter-ranean region and is considered a cool-season annual. It flowers best in cooler weather and tends to fizzle during the hottest weeks of the summer. Some research suggests that it has medicinal qualities. The pot marigold readily seeds itself and will return from seed the next spring. This is its greatest advantage over the other two marigolds.
The African and French marigolds are warm-season annuals that thrive in the hotter months of the summer. They have strongly scented foliage, which is another way to distinguish them from the pot marigold, whose foliage is scentless.
I am preparing to grow some of my own vegetable seedlings indoors this winter. A book says the seedlings should be thinned after they germinate. What does this mean?
Many vegetable seeds are very small and are easily planted more densely than is best for their growth. When this occurs, the seedlings are "thinned" to prevent them from crowding each other out. For example, if you were starting spinach indoors, you might sprinkle 50 seeds in a flat, but shortly after they begin growing, you would thin them by pulling 20 of the seedlings out. This would give the 30 remaining plants enough space to grow before being transplanted to the garden. You should also thin crowded plants that have been directly sown in the garden. This is often done with carrot seedlings.
1. De-icing salts can seriously damage lawns and plants. Use them sparingly in the vicinity of plants. As an alternative, throw down coarse sand to provide traction in icy spots.
2. Baltimore City's curbside leaf pickup ended Dec. 29. However, leaves can still be taken to one of the city drop-off stations.
Dennis Bishop is an urban horticulture educator for the Baltimore office of the Maryland Cooperative Extension Services. If you have a gardening or pest problem, you can call the Home and Garden Information Center hot line (Monday through Friday, 8 a.m. to 1 p.m.) at 800-342-2507. You can also e-mail questions, order publications and diagnose plant problems by visiting the Web site www.hgic.umd.edu.