The Harris Seeds Home Garden Trials for 2013 are set to begin. I’m just waiting for the night-time temperature to get to a predictable 55 degrees and then I can start planting.

This is my second year to be invited to be part of the company’s trialing program. In addition to testing several varieties of flowers, peppers and tomatoes, Harris Seeds is interested in evaluating three varieties of grafted heirloom tomatoes.

Grafted vegetables are working their way onto the pages of seed catalogs and into neighborhood nurseries and garden centers. By grafting a tasty, heirloom tomato onto a tougher rootstock, the plants grow to be stronger and more resistant to soil-borne diseases and stressful growing conditions.

The results of this trial will help Harris Seeds decide which varieties the company will consider adding to its catalog in the future.

The trial tomato sampler includes grafted and non-grafted Pink Brandywine, Cherokee Purple and San Marzano tomatoes for a side-by-side comparison. 

I’ve already reported on how the plants looked when they arrived. Because this is a trial program, Harris Seeds wanted feedback on plant quality (leaf color, stem quality and general vigor); shipping quality (plant damage or dislodging from cells); and whether a printed planting guide and plant identification legend were included.

Planting information is always important, but it’s especially essential for grafted plants. The graft needs to be planted at least one inch above the soil line. If the graft is planted below the soil line, the grafted (scion) plant will begin to root in the soil. This means the plant will bypass its grafted rootstock, which defeats the purpose of having a grafted plant.

The planting guide gives step-by-step instructions for choosing the right planting location, preparing the soil, mulching and watering. Care after planting includes keeping the plants consistently moist, fertilizing every 2-4 weeks, protecting them from frost and adding tomato supports or cages.

All of the care instructions are meant to help get the best results during the testing process.

Later this season I’ll report my results. The grafted tomato evaluation asks gardeners to rate transplant quality, plant vigor, disease resistance, weather tolerance, and yield. The tomatoes will be rated on taste (flavor, texture, aroma and culinary appeal) and quality (appearance, consistency and uniformity).

If non-grafted plants are grown alongside the grafted heirloom tomatoes, gardeners are asked to evaluate any visible difference in plant vigor, yield and disease resistance.

Because grafted tomatoes are more costly to produce, there are also questions about pricing and whether grafted tomatoes are worth the added expense. 

I’m looking forward to being part of the home garden trials and to sharing some of my experience with you during the season and after the harvest.

Have you grown grafted tomatoes in your garden? If so, please share comments about your experience (positive or negative).