It’s hard to quantify the qualities of a carrot that make it worth growing in your own garden — but my ideal carrot has a certain amount of sweetness coupled with just the right amount of crispness. Unfortunately, however, most of the carrots I have eaten over the years do not match this ideal.

Although carrots are indispensable in many dishes and inexpensive for much of the year, I wouldn’t get rapturous about them. I might put them in stew or set some out as appetizers to balance the salty, high-fat treats most of my guests prefer. Utilitarian, hard working and ordinary, carrots will never have the glamour of radicchio or summer tomatoes.

Each year, however, members of the Napa County Master Gardeners choose a vegetable to field test in their home gardens. The objective is to find the varieties that perform best locally, so that we can recommend them with confidence to others. Despite carrots’ unassuming reputation, the committee chose them for growing this year. Acknowledging the difficulty of evaluating flavor or crispness, we agreed to measure and compare only by weight.

We chose carrots in three different colors: orange, yellow and red, and committed to planting the same number of blocks of each type at about the same time in the spring. We also agreed to follow good cultivating practices, so we discussed what carrots need and tried to give them similar care. Finally, we agreed on a uniform way of harvesting so that we could compare results from the various Napa County locations.

Carrots grow best in loose, sandy soil that is free of rocks. My native Napa soil is more clay than sand, and has a considerable amount of large gravel in it. I regularly add compost and other organic amendments to improve its health, but I decided to sift the carrot soil first to remove the largest pieces of gravel.

Because my garden is also gopher habitat, I dug down about a foot and placed cages made of half-inch hardware cloth into the ground to exclude the gophers. When I added back the soil, I sifted it through an old milk crate which had a one-inch grid of openings. It caught the gravel nicely. I hoped that precaution would prevent the carrots from hitting rocks and growing forked roots.

Carrots prefer an average amount of nutrients in the soil. Too much nitrogen can cause misshapen roots. If you do add fertilizer, avoid fresh manure or high-nitrogen mixtures. In my garden I did not add anything to the planting area except well-aged compost.

Carrots should be planted directly in the soil where they are to grow because seedlings don’t transplant well. Sow the small seeds evenly and cover them lightly with soil. Because the seeds are slow to germinate, many gardeners use sand, perlite, old compost or other covers to keep the soil moist and prevent crusting. I put finely sifted compost over the seed and misted the area every day until the seeds germinated, which began 11 days after I planted and continued for another 10 days.

Five weeks after planting, the baby seedlings were three inches high, tall enough to tell them apart from the weeds. The next task was to thin them to at least a half inch apart. That’s when I noticed something was eating them. A late-evening trip to the garden with a flashlight revealed the culprits: Earwigs. I crushed the ones I could see and set out some rolled-up newspapers to trap more. The carrots survived with minimal damage.

Eight weeks into the project, I thinned the carrots again. To reach full size, carrots need to be about two inches apart. When I was finished, I had 12 carrots growing in each of the blocks where germination had been optimal. Some blocks had poor germination and required no thinning.

Harvest began 75 days after sowing. You can get an idea of how large a carrot is by feeling its shoulder just under the soil surface. Most of my carrots were about six inches long and weighed between one and two ounces.

The field test committee has not yet finalized its results, although nine gardeners have reported their outcomes. My yield in weight was low compared to other sites, probably due to the spotty germination. Statistically, all the varieties in my garden performed similarly.

Despite my comparatively low yields, I was pleased with the results. I harvested a little more than 13 pounds, which was plenty for my household, and I didn’t lose any to gophers or rabbits.

I enjoyed the different colors of the carrots: The red carrots had a beautiful skin color but were orange inside; and the yellow carrots were pale yellow all the way through. When I picked the first batch of carrots, I also picked some late snow peas. Together, they made a colorful and nutritious dish for the dinner table.

And yes, some of those carrots — eaten straight out of the garden — were sweet and crisp, just the way I like them.

Napa County Master Gardeners are available to answer questions in person, by phone or on their Web site. Call 253-4221 or visit www.mastergardeners.org for information.