Laura,

Thanks for reaching out!
And glad to hear you’re thinking about the health of your plums and pear trees. Since I’m not certain what prompted the decision to fertilize your trees this year – I’m going to offer some additional information. Take from it what you will.

For a small investment, routine soil analysis can establish your soil's fertility level and determine if any corrective measures are required. Soil testing is the most effective tool available for determining fertilizer needs to produce healthy plants (and protect the environment). Soil testing removes the guesswork and prevents the risk of over or under fertilizing. UVM Extension Soil Testing Lab can provide this service (link below).
Whatever you do, don’t overdo the application of fertilizers. Too much fertilizer can be as detrimental as too little, particularly when it comes to nitrogen. Nitrogen fertilizers, represented by the first number on the fertilizer bag, fuel the annual extension growth in the trees.

You generally should get about 18 - 24 inches of annual extension growth during the first several years. Thereafter, 10 - 12 inches is sufficient for mature trees.

Cornell Cooperative Extension tells us, as a general rule, determine how much fertilizer to apply based on the guideline in the chart below.

These are the rates that you should apply if your trees are not producing enough annual extension growth as described above. Note that the amounts are small, but don’t be tempted to over-apply. Over-fertilization with nitrogen, phosphorus, and potassium can cause deficiencies in other nutrients. If your trees are growing as described, then don’t apply fertilizer and reevaluate next year.

Nitrogen  rate	33% N	10-10-10 10% N	20-20-20 20% N
Young trees	.04 lb./tree	2 0z./tree	6 0z./tree	3 0z./tree
Mature trees	.08 lb./tree	4 0z./tree	12 0z./tree	6 0z./tree

     
If your trees flower every year but don’t produce fruit, a micronutrient deficiency might be the cause. After eliminating other possibilities, such as late frosts, a leaf tissue analysis might be the best option.

Compost/Nitrogen: Total nitrogen includes organic, ammonium, and nitrate nitrogen. The normal range for total nitrogen in finished composts is 0.5 to 2.5 on a dry basis. Ammonium levels will decrease as the compost matures or ages. Since you’re purchasing bagged VT Compost, the company may be able to tell you the nitrogen levels to expect from their product so you can determine your rate of application.

Compost Tea is a whole other research paper. I firmly believe straight up compost is the winner every time. It’s handy and the nutrients you need for your soil and plants are right there. With compost tea there seems to be a lot more questions concerning whether it truly works or not. And there are so many variables. Then there’s the time and effort to put into making it. There are food safety concerns and the potential for disease causing illnesses, like coliform bacteria and Salmonella.  The USDA report (https://www.ams.usda.gov/grades-standards/soil-building-manures-composts) which included:

• Use only potable water to make compost tea or to dilute it.

• Sanitize all of the equipment used to prepare compost tea.

• Make compost tea only from compost that has maintained a temperature of at least 131 degrees F. for 3 days and has been mixed so all of the pile or windrow has heated up.

• Avoid additives when fermenting compost tea, as these can promote the growth of harmful organisms. In particular, simple sugar sources, like molasses, should be avoided.

• Additives can be used if sample batches of compost tea are tested before using it to make sure it meets the EPA’s recreational water quality guidelines for coliform bacteria.

• If compost tea is made with additives but is not tested, or if it doesn’t meet water quality guidelines, then food crops may not be harvested until 90 to 120 days after the compost tea has been applied (as with raw manure use on organic farms).

Compost tea – Miracle or Snake oil? https://extension.illinois.edu/blogs/good-growing/2019-08-14-compost-tea-miracle-product-or-snake-oil

Resources -
UVM Extension Soil Testing Lab, Soil Samples: https://www.uvm.edu/extension/agricultural-and-environmental-testing-lab

Interpreting your soil test, under the Soil & Health tab at the Extension Resources Page: https://www.uvm.edu/extension/mastergardener/gardening-resources

Additional resources:
https://netreefruit.org/pears

https://ecommons.cornell.edu/bitstream/handle/1813/67/Cornell_Guide_to_Growing_Fruit.pdf (P. 14 for fruit trees)

https://ag.umass.edu/home-lawn-garden/fact-sheets/fertilizing-guidelines

I’ve likely offered you more information than you needed. But I do hope this is all helpful. Fingers crossed the cold snap doesn’t deter the fruit trees from producing this year!

Ah thanks so much!