In a small garden plot behind the Unity College Library, several master gardeners, along with Extension educator Rick Kersbergen, have turned a goldenrod-ridden weed patch into a productive vegetable garden. Last week, it was the site of a tomato tasting put on by Kersbergen and the master gardeners.

I attended the event and was so interested to see what was going on in the garden, I almost forgot to taste the tomatoes. The garden is an exciting combination of design ideas, experimental plots and variety comparisons. Although the tasting was supposed to focus on tomatoes, there were plenty of sweet pepper and hot pepper varieties to compare, and a few types of melons.

The idea materialized when Dan Goerhring, Unity College provost and master gardener-in-training, sought to revitalize the floundering community garden on campus. He consulted Kersbergen, and with the help and enthusiasm of other master gardener volunteers, they revived the garden spot.

One-third of the garden is still dedicated to and cultivated by Unity residents and Unity College students. The two-thirds of the garden that is under the care of the master gardeners is a potpourri of ideas that makes it a learning tool for the gardeners and all who view it.

On one end, a weed control trial is being conducted. The gardeners are testing the effects of various cover crops on weed suppression. Each of five small plots contains either barley, oats, sorghum-sudangrass, buckwheat or a mixture of oats, peas and vetch. Clear plastic mulch — used for solarization which heats up soil and kills weed seeds before they are able to germinate — also is being tested. Not a weed is growing under the plot with clear plastic mulch, and the cover crops too are doing a good job at keeping the weeds down.

Cover crops typically are tilled in to release “green manure” into the soil. But some of the covers, especially the mix of oats, peas and vetch, can be tough to get rid of with the rototiller. Instead of tilling this cover crop under, Kersbergen mowed it a month ago. Now that area is nothing but dead stubble, providing a vertical mulch that a fall crop of greens, kale or mums could be planted through.

Kersbergen cautions that although many crops can be used for cover in Maine gardens, some crops are better than others. Buckwheat, for example, makes a good cover — it can be seeded, tilled under and reseeded several times during the season — but can convert to garden weed if a gardener fails to be attentive, letting it go to seed. In general, oats, barley, and wheat are good cover crop selections for the early season, when it is cool. Sorghum-sudangrass is a better selection for a midsummer cover.

After touring the rest of the plot, which features a children’s garden, a dry bean trial space, and many varieties of tomatoes, peppers, along with a dash of cole crops, it was tomato tasting time. The list of varieties was long and delicious. Sun Gold and Matt’s Wild Cherry tomatoes were displayed. Staple varieties such as Celebrity, Early Girl and Jet Star were shown alongside heirloom Brandywine. Roma, a variety excellent for paste, also was shown. Many others were sampled.

If you would like to view the demonstration garden for yourself, you’ll find it behind the Unity College Library. The campus is on Quaker Hill Road in Unity. From the library parking lot, follow the row of crabapple trees across the soccer field and to the woods.

This is the first year the demonstration garden has been under cultivation. If you don’t make it to the garden this season, you’ll likely find another crop of plants there next season.

Extension educators statewide offer the master gardener training program annually. Thirty hours of intensive training is exchanged for 30 hours of volunteer time. Each year the course offers basic training in gardening techniques. From year to year, emphasis alternates from vegetable gardening to gardening with ornamentals. For more information contact your local Extension office. To obtain a toll-free telephone number for the Extension office nearest you, call the state headquarters at the University of Maine in Orono at 1-800-287-0274.

Diana George Chapin is the NEWS garden columnist. Send horticulture questions to Gardening Questions, c/o MaineWeekend, Bangor Daily News, P.O. Box 1329, Bangor 04402-1329. Selected questions will be answered in future columns. Include name, address and telephone number.