Fourteen garden members recently had their soil tested at Wallace Labs and they have shared their results with us so that we can provide you with some valuable information.  Here are some of the important details:

Our soil is very fertile and rich in nutrients.  To keep it maintained you usually need 3 things:

• A nitrogen fertilizer such as calcium nitrate, fish emulsion, blood meal, feather meal.
• Gypsum is very important to improve soil drainage and reduce salt buildup.
• Some compost/manure to improve tilth and add nutrients.

Keep it simple and add only what you need.  There is no need to buy additional nutrients or spend money on blended fertilizers and enhanced composts.

Some of the problems reported were:

Salt

All of the plots had moderate to high levels of salt.  Salt makes it harder for plants to take in nutrients. They grow slower and don’t produce as much.  Manure and nitrogen fertilizers contain high levels of salt.  It is important to add gypsum to your soil and water deeply to leach out the salt.

Zinc

Zinc is an important nutrient but too much inhibits growth.  Our native soil has a very high level of zinc and it doesn’t need to be replenished.  It is suggested not to add fertilizers that contain zinc such as Miracle Gro, Azomite, Ironite, and Bumper Crop compost.  Check labels.

Aluminum

A few plots had high levels of aluminum which restricts growth.  Aluminum is usually sequestered in soil but can become plant available when the soil is stressed such as low pH (acidic) or poorly aerated conditions.  Make sure your soil is not too compacted from over-watering or lack of organic matter.

Acidic soil

Most of the plots had pH values in the desirable range (neutral) but a few had low values.  Sulfur is an important nutrient but too much makes the soil acidic.  If you are using pH lowering fertilizers such as ammonium sulfate, you might want to check your soil pH with a test kit found at garden stores and online.  If your pH is around 7 or less, consider switching to a pH neutral fertilizer like calcium nitrate.

The garden website has been updated with new recommendations and soil preparation examples.

You can request a full analysis of the soil test results from orchard manager Alan Coles at lbcg.orchard@gmail.com.  I will be happy to answer any questions you have.

Alan