It’s June, which means full-tilt growing season. With all the activity – plants growing, farmers farming, microbes multiplying – it’s good to know whether you’re giving your microbes what they need. Here are a few things to keep in mind.
If you started preparing your growing system last fall, and your microbes have successfully established, now is the time to hold steady. Keep an eye on moisture, and do everything possible to avoid compacting your soil.
That means limiting vehicle and foot traffic, but it also means covering the surface. Remember, falling water compacts bare soil, so keep your ground-cover plantings healthy. If your system still lacks a continuous ground cover, maintain a generous layer of carbon-rich mulch material.
Most crops, especially vineyards and orchards, need as much fungal growth as you can nurture, and avoiding compaction is essential to fungal development. All organism groups suffer when soil is compacted, but especially fungi.
For soil moisture, you’re aiming for somewhere in the range of 35-50 percent, depending on soil type. The best way to gauge moisture is by tightly squeezing a healthy handful of soil; it should just begin making a squishy sound. If a drop or two emerges between your fingers, you’re at about 50 percent. That’s perfect for soils with good structure.
In nursery work, regular microbial applications are key. It can be a challenge maintaining biology when plants become root-bound in small pots, especially in the summer heat. Soil microbes survive dry conditions by entering dormancy, but most aren’t equipped to handle the quick moisture swings that can happen in a nursery pot. If they can’t transition quickly enough, they don’t survive.
That means a proactive approach is best. Depending on your production setup, a sprinkling or misting system can be useful, helping to maintain surface moisture as temperatures rise (another problem solved by continuous ground-cover plantings).
If you’re adding a microbial-inoculum product during transplanting, choose one that contains at least a dozen species. And remember, if you’re adding mycorrhizal spores, apply them directly to roots. That means water the spores in well, to reach feeder roots near the surface; and apply them to root balls when transplanting. Mycorrhizal species will ‘awaken’ when they encounter moisture, but they won’t survive if they don’t encounter a plant root within a few hours.
Higher-quality products contain a number of both bacteria and fungi. However, many also contain Trichoderma, an aggressive fungus traditionally considered beneficial for its use in controlling other fungi, namely pathogenic ones. The problem: Trichoderma don’t just eat pathogens, they also consume the aerobic fungi you need. So except under specific circumstances, avoid products that contain them.
Perhaps a helpful way of looking at all this: our primary job is to care for the smallest of animal lifeforms – so in a sense, we are ranchers first and foremost. Get a feel for the conditions that make your microbes comfortable, and always be striving for those conditions.
And until you’ve got your system dialed: always confirm as you go.