Chestnut Orchard Soil and Leave Sampling

When to Take Samples

There is one thing most experts agree on when it comes to taking soil and leaf samples, always take the samples at the same time of the year. But even this has some issues. The time of the year is more dependent on what the chestnut trees are doing than the actual month and day of the year.

For leaf samples the recommended sample collection time is when the chestnut trees are blooming. Do not collect before this time because the tree may still be using stored energy reserves from the prior growing season. If your chestnut trees bloom at different times wait until the last one is done blooming to collect samples. Take samples first thing in the morning before the dew is off the grass. Store the samples in a plastic bag and place in the refrigerator over night. Ship the samples to the lab the next day.

Soil samples are normally taken in the fall. Here in the Pacific Northwest we get so much rain during the fall, winter, and spring that fall sampling would be very different as compared to the start of the growing season in the spring. Soil samples in early March would be best if there is still enough time to get the results back and have the fertilizer formulation done. In Northwest Washington the chestnut growing season doesn't start until mid to late April. Appling fertilizer before this time is a waste since it might get washed deep into the soil where it would not be available to the chestnut trees. So soil sampling is more dependent on the weather conditions (like frozen ground) than anything else. Check with your local farm extension office for the best advise about when to take soil samples in your area.

How to Take Soil Samples

Soil samples should be taken between the trees from the bare ground band a 2-3 feet inside and past where the branches extend to (the drip line). Remove any surface organic matter such as grass cuttings, leaves, moss or other vegetation. Take samples to a depth of 6-7 inches. Take 15 - 20 samples from the orchard using a zigzag pattern through the orchard and mix in a bucket. Remove 1 - 2 cups of the soil and place it in a sample submission bag (available for soil testing labs). Send the samples to a reliable laboratory.

How to Take Leaf Samples

Collect 40-60 leaves, no more than 2 leaves from any one chestnut tree, from the middle of this current season terminal shoots. Select shoots 5 to 7 feet above the ground with average vigor (look for the vigorous growth at the end of the branches exposed to full sunlight). Collected leaves should be placed in a clean plastic bag. When collecting samples remember chestnut tress do not produce nuts on shaded branches, so do not take leaves from shaded branches. Be careful when collecting the samples so you do not damage the branches.

Trees sampled should represent the average condition within the orchard unless special samples are being taken to determine cause(s) of a distinct problem or condition.

Avoid strong vigorous shoots near pruning cuts and extremely week shoots. Do not include spur leaves (the first leaves to develop on the tree from dormant buds on the short lateral shoots, shoots usually less than 6 inches long).

Do not mix leaves from trees of different ages (young seedlings trees with nut bearing trees).

Do not collect leaves that are damaged by diseases, insects, or whatever else that can injure leaves.

Selecting a Testing Laboratory
Up to this point the task of taking samples was easy. Finding a good testing lab is not so easy. We have tried several over the years and have yet to be completely satisfied. Here are a few tips for the selection criteria:

Do they have experience doing the kind of testing you are requesting.
How long does it take to get results once they receive the samples.
Are they consistent with the quality of the testing and test results.
Can they present the results in a form you can understand.
Do they use industry standard measurement units on the test results.
Can they provide some advise about the test results.