I get so many questions about this topic, so here are some answers
Fall is THE best time to fertilize with organics. First of all, since they are slow release, they are slow to break down and so fall - with its attendant rains -starts the breakdown process. BUT, due to cooler soil temps and lower N values, the plants don't needlessly convert the nutrients into excessive vegetative growth. Instead, they plants start building up the storage pantry -- which is what will be needed for the spring flush, when reserves would otherwise be depleted.
Also, building up a robust root structure is what will help your plants prevent frost damage. Our winters have been a bit whacky, but what has been a pattern is a few weeks of super cold weather. You need to freeze proof your plants. A good fall fertilizing with Hendrikus Organics, which offers an ample supply of beneficial soil microbes will help in this process. Similarly, with all the rains the winter months will bring, a robust root structure will utilize the water better.
Fall is also the time of year to amend soils and build the best soil structure. Increase organic matter through compost -- and humate (HuMagic), and food sources that will feed both the plants and the microbes. HO ferts contain at least 22 different species of beneficial microbes. The microbes do much of the work in making nutrients available, but they also are the carpenters improving soils "architecture." Increased pore space and aggregates of soil particles are necessary to drain te heavy rains. Otherwise, you will have soggy soil which can not breathe. The anaerobic conditions lead to death of beneficial microbes -- and root rot! )= sick plants)
Lastly, fruit bearing plants such as blueberries are setting their fruitbuds now for next year. Fertilize now to get the best yield next year. Similarly, the berries come out of the winter "starved." A good fall fertilization will give them the nutrients they need to get producing more effectively during the growing season.
Liquid HuMagic: Stressed trees & shrubs. Treat with soil drench all around the drip line. Do a foliar leaf spray for Non-Conifers. (conifers breathe through their needles so we don't recommend spraying needles). The Humagic contains a mixture of benefical organic acids: Humic, Ulmic, and Fulvic Acid. The fulvic acid in particular, has a very low molecular weight -- which enables it to pass immediately through the cell wall where it immediately works to chelate minerals in forms useful to plants. The synergistic effect of the organic acids serves to improve metabolism, nutrient efficiency, and disease resistance.
Japanese & Vine Maples have been particularly stressed by the long drought period. While they are attractive now, in terms of their characteristic fall color, most maples are still a bit flacid and lack the vigor and pop they usually display. Perk them up and help them build up for winter stresses with applications of Liquid HuMagic: They will respond quite happily to soil & foliar drenches. Mix at rate of 2oz/gallon, apply every two weeks -- or for more immediate perk up and improved appearance, root enhancement and disease resistance. The difference will be noted in leaf branch stem, vigor, and leaf thickness. Sometimes more intense color.