How to Grow San Marzano Tomatoes

The San Marzano tomato is thought to be the best tomato in the world for making pasta sauce. Grown in the rich volcanic soils near Mt. Vesuvius, they are thicker and sweeter than Roma's and have a stronger, less acidic flavor. While there is no guarantee that a home grown San Marzano will taste exactly like the ones grown in Italy, the adventurous gardener can find seeds, and sometimes seedlings, available over the Internet. With proper care, a few of these indeterminate vines can keep you in sauce for months.

San Marzano tomato seeds

Peat pots

Compost

Mulch

Stakes, half an inch thick and eight feet long

Shade cloth (optional)

Purchase San Marzano tomato seeds or plants from a reputable nursery. Plant the seeds in individual peat pots six to eight weeks prior to the last frost. Water the pots thoroughly and place them in a sunny window. Under normal conditions, San Marzano seeds will germinate in six to 10 days.

Search for a planting site. San Marzano tomatoes need full sun to grow well, so choose a location that receives sunlight for at least seven hours per day.

Prepare the chosen spot by overturning the soil with a spade or shovel and adding approximately seven pounds of compost for each square foot of garden area. Work the compost into the top two to four inches of soil.

Once the seedlings have at least two leaves and are a minimum of three to five inches in height, they are big enough to transplant. For each tomato plant, dig a hole four to six inches deep. Place the peat pot into the hole and adjust the depth, if necessary, to allow you to bury the entire plant, permitting only the top two leaves to be exposed. Leave 18 to 24 inches of space between each seedling and 36 inches of space between each row.

Position the transplant in the center of the hole and push the dirt back around it, gently pressing to compact the soil around the main stem. Within 10 minutes of plating, give each seedling one gallon of warm water as this will help prevent 'transplant shock' and encourage outward root growth.

Give new transplants two cups of warm water each day for one week. After one week, water the plants two to three times a week, depending on the amount of natural rainfall in your area. In dry climates or extremely hot weather, the watering schedule may need to be increased.

Place mulch around the tomatoes 14 days after transplanting them. This will help the surrounding soil to retain moisture and will help prevent the growth of weeds. Spread the mulch around the base of the plant, creating a circle that is one inch thick and 12 inches in diameter.

Stake the tomato plants six weeks after transplanting. Choose stakes that are half an inch thick and eight feet long, as the San Marzano tends to be a somewhat longer vine than your average tomato. Insert the stakes into the ground, planting them about 18 inches deep and three inches away from the base of the tomato plant. Tie the plant loosely to the stake to allow for continued plant growth.

Agitate the plants when they begin to bloom. Two times a week, gently shake the main stalk as this will help to distribute the available pollen. This leads to an increase in fertilization and an overall amplification to plant yields.

Wait 40 to 50 days after transplanting for tomatoes to appear. San Marzano vines tend to start bearing fruit a bit later in the year than some of their rivals, but once they begin, they are prolific producers offering a bountiful harvest until the first hard frost. The 3- to 4-inch tomatoes grow in small clusters that are ready to pick when they turn a deep, bright red.

If the temperature is expected to rise above 95 degrees, you should consider covering your tomatoes with a shade cloth.