The element boron (B) is a plant micro-nutrient and deficient in many Alaskan-area soils, including in the Chilkat Valley. Boron is easily leached away where soils are seasonally saturated with water.

In 2021-2022, the Chilkat Valley Orchard Project collected and analyzed about 30 local soil samples, ranging from tidewater to near the Canadian border. Only three of the 20 showed boron in the “good” range, (0.5ppm – 1ppm). Seven of these samples were at or below 0.2ppm (very deficient). The average boron value was about 0.4ppm and below the “good.” 

Why Boron? Adding a little boron is useful for many local veggie/fruit producers. Boron is used in the pollen tube structures of flowering plants. For fruiting crops, like raspberries, apples, plums and cherries, deficiency reduces fruit setting. You don’t want that! Boron also plays a role in plant protein synthesis and the uptake and transport of macro-nutrients: calcium, potassium, phosphorus, etc. Brassica crops have a “high response” to boron. Broccoli, beets and turnips are particularly needy.

A general agricultural level for boron, recommended by Michigan State University, is two pounds per acre which equates to one part-per-million (1ppm). This concentration is over twice the level of most Haines soils.

The uptake of boron, and most plant nutrients, is optimized by soil acidity in the range of pH 6.0 – 6.5. Plant nutrient absorption is diminished when soil pH (acidity) falls below 6.0—common in the downtown and tidewater areas of Haines.

Applying Boron to an Orchard/Garden Space: It’s a micro-nutrient! “More” is the wrong answer. Measure and apply carefully. The cheap way is to purchase 20 Mule Team Borax (14.5% Boron by weight). Given local soils, increasing soil Boron by 0.5ppm (parts per million) is safe and beneficial. If you’re already using huge, annual gobs of seaweed, skip it. For each 100 square feet, adjusting 0.5 ppm requires 7.3 grams of 20 Mule Team Borax. Not much!

This amount will definitely keep boron below 2.0ppm, which is around the level where this slippery element begins to become toxic to plants. Two level teaspoons—each just slightly light—give you about 7-grams of 20 Mule Team Borax.

Dissolve the powder in a bucket of water and apply the solution evenly over the measured area with a watering can—evenly, back and forth. For 200 square feet, double the amount, 300 square feet, triple, and so forth. A 12’x 4’ raised bed (48 square feet) requires one light-level teaspoon (3 to 4 grams), etc. Boron’s ability to quickly leach away means a possible ritual, every few years.  

More about CV soil nutrition: On the website of the Chilkat Valley Historical Society select “Orchard Project.” Then navigate to the “Resources” menu and select Nutrient Notes Fruits and Berries. Better yet, download Blythe Carter’s beautiful, 28-page PDF Growing Fruit Trees in the Chilkat Valley.

Thinking about planting a fruit tree? Seek no further. Everything you need to plan, order, and grow healthy fruit, and nurture productive, living soil is there. All free from the Chilkat Valley Historical Society.