Employing Microbes Against Replant Syndrome

It's easy to take a peach tree for granted. We expect that when Farmer Al plants a peach tree, it will grow tall and strong and produce the delicious fruit we love, year after year. But after 20 to 25 years of producing fruit, though we nurture our trees throughout their lifespan to keep them strong and productive, peach trees come to the end of their life. And when this happens, we must remove them and replant new trees in their place. The growth cycle starts again – just like that, right?

Not exactly. First, we have to prepare for replant syndrome.

What is replant syndrome?

Replant syndrome is stunted growth. When you plant a new tree in new ground, it takes about 3 to 5 years for the tree to reach maturity. But when you plant a new tree in a hole where an old tree was growing, it can take twice as long for the tree to reach maturity. We think that old root systems leave microbes in the soil that stunt the growth of new trees. So, to help prevent replant syndrome, we inoculate both the soil and the root system of the new trees with a diversity of beneficial soil microbes. 

Shifting the soil biome 

Changing the microbial environment in an orchard is a big job. This year we pulled out a 4-acre peach orchard of Cal Reds and O’Henry’s and replaced it with a Summer Flare nectarine orchard. After the old peach trees had been taken away, we used powerful, 2-foot steel shanks to break up the soil, so it was nice and loose for planting. 

Then we added our compost which contains billions of microscopic organisms to the hole to encourage vigorous new growth.

Trees thrive on beneficial bacteria, so our next step was to spray each and every root on every tree with a mix of water and a diversity of beneficial bacteria. These bacteria create a rhizosphere – a complex world of microorganisms that support our new trees' vigor and health by increasing nutrient absorption and cycling and protecting the new tree from pathogens. 

Then we placed the trees in the earth and covered the roots with more compost. We’ve done everything we can to prepare the soil and our new trees. For the rest of their lives, we’ll ensure they have everything they need to be healthy with frequent compost application, green mulch, and excellent care from our skilled tree team. 

new orchard and spraying roots
Left - Our new nectarine orchard this summer
Right - Spring planting spraying the roots with beneficial bacteria 

What's next?

Like everything in farming, results take time and patience. We learn from experience. A few years ago, we prepared an orchard for replant syndrome, and those trees are doing well today. We think we have cracked the code, but we’re still watching and waiting. We expect good results with our new, 4-acre orchard of Summer Flare nectarines, which to date is looking good.  We’ll keep you posted on our new orchard’s progress!

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