The Dirt Gardener's Column for May 15

Q. I have a three-year old dwarf Robertson's navel orange that looks great with lots of new growth. Last year it had about six oranges that never matured. This year, I have about thirty but they’re still hard as a rock and somewhat green. Should I continue to leave them on the tree, try to ripen them indoors, or just give up on them?

A. Robertson and Washington are the primary varieties of navel oranges. They’re called navel oranges because they have a characteristic depression or belly button opposite the stem end. Navel oranges are considered the finest orange for eating, as they’re juicy, seedless, are easy to peel and segment. Robertson Naval is very similar to Washington expect it ripens a couple of weeks earlier. For home gardens, this isn’t significant, so when selecting between the two varieties you pick the best-shaped plant. Navel oranges can ripen as early as November with January through March being their peak season but they can mature later. Dry mealy fruit results from not enough or irregular watering during the summer months and sour tasting oranges is from a lack of summer heat. The fruit will sweeten up when left on the tree; however, they will not become juicier. In addition, oranges do not ripen off the tree like persimmons, pears, or avocados. This being said, I’m inclined to believe that your orange was mislabeled. If it has a naval than it could be Late Lane also referred to as the summer navel. Late Lane is similar to Washington Navel with a smaller naval has a smooth skin and ripens six to nine weeks later than Robertson. With no navel, Valencia Orange is very likely. Valencia Orange is smaller than a naval, has seeds and ripens during the late spring through the summer. It is the primary variety used for juice. So, I wouldn’t give up, yet. Instead, I would wait and see what happens. At the end of the month, I’d pick one, taste test it and continue to do so every three weeks.

Note: When started from a seed, the growth is bush-like, dangerously thorny, and the fruit is unpredictable. Oranges are typically grafted from a desirable parent and produce for a lengthy period of time, seventy plus years.

Q. I have always used vegetable seeds from previous years with seemingly no ill effect. What is the lowdown on using older flower seeds?

A. Flower, or vegetable seed deteriorates the older it gets. Temperature and moisture are the primary causes for the decline in the germination rate of seed. They’re best stored in a closed plastic or glass container and kept in a refrigerator or any other cool location. There is a simple test to determine if old seed is still good. You fill a clear jar or glass with water and dump in the seed. The good seed is heavy and sinks to the bottom of the container. Another method is to sow the seed in a flat instead of the open ground. You then transplant the vigorous seedlings.

by Buzz Bertolero, CCNP