bonsaiTALK Community - View Single Post

Ok ya'll asked for it. *Here's my opinion on fall feeding. *(This stuff applies for plants and I'm guessing that tree physiology isn't that much different) (Also, I'm a soils guy and its been a long time since I've had a plant phys class so if anyone knows any differently, don't hesitate to say so). *From what I've gathered, tropicals that don't go dormant should get a balanced fertilization throughout the year. *However, you need to cut back on the nitrogen (not necessarily eliminate) in the fall. *Nitrogen does promote growth in a plant that is not dormant. *Nitrogen is a key element in photosynthesis so no N = no photosynthesis = no carbohydrates = no energy = dead tree. *The N problem is that enough must be added to maintain photosynthesis but not to encourage growth. *Since trees are quite a bit different, this will be on a case by case basis. *Add enough N to keep the tree green but limit leaf production. *Even though tropicals don't necessarily go dormant, I seem to recall that they need a "resting period" of slower growth in order to continually produce new growth every year. *This period can be brought on by shorter daylengths instead of lower temperature in the fall and winter. *That's the tropicals.

Let's go to trees that do go into a full dormancy during the cooler months. *This is where I really differ from Jim's view. *A lot of different things go into promoting growth. *Hormones, daylength, temperature, and above all soil fertility. *Try growing a plant without the 16 macro and micronutrients and see what you get (dead tree) or add N during a normal growing season and watch the results. *You'll have more growth than you know what to do with (or, on a bonsai, more than you can prune.) *The secret is to manage fertility based on the tree's needs. *During the summer, higher rates of N will promote vegetative growth while higher rates of P and K will promote reproductive growth (flowering). *Fertilization with N,P, and K later in the growing season is extremely important in preparing the tree for domancy. *During this time, as days get shorter and cooler, the plant begins storing carbs for the next growing season. *For this, N rates need to be reduced so little or no new growth occurs. *You still want enough N for photosynthesis but not so much for growth. *P and K rates need to be held constant so carb production is maintained. *Once the tree is into full dormancy, fertilization can be stopped.

All right, *by now I've probably honked some folks off so I'll quit. *If anybody wants me to, I'll talk about soil fertility and especially availability and fertilizer form (i.e. organic vs. inorganic (they both have benefits, but a plant only takes up inorganic forms).

4-Oct-2001	#3
Soildoc bonsaiTALK Expert Join Date: Sep-2001 Posts: 169	Re: Fall feeding Ok ya'll asked for it. Here's my opinion on fall feeding. (This stuff applies for plants and I'm guessing that tree physiology isn't that much different) (Also, I'm a soils guy and its been a long time since I've had a plant phys class so if anyone knows any differently, don't hesitate to say so). From what I've gathered, tropicals that don't go dormant should get a balanced fertilization throughout the year. However, you need to cut back on the nitrogen (not necessarily eliminate) in the fall. Nitrogen does promote growth in a plant that is not dormant. Nitrogen is a key element in photosynthesis so no N = no photosynthesis = no carbohydrates = no energy = dead tree. The N problem is that enough must be added to maintain photosynthesis but not to encourage growth. Since trees are quite a bit different, this will be on a case by case basis. Add enough N to keep the tree green but limit leaf production. Even though tropicals don't necessarily go dormant, I seem to recall that they need a "resting period" of slower growth in order to continually produce new growth every year. This period can be brought on by shorter daylengths instead of lower temperature in the fall and winter. That's the tropicals. Let's go to trees that do go into a full dormancy during the cooler months. This is where I really differ from Jim's view. A lot of different things go into promoting growth. Hormones, daylength, temperature, and above all soil fertility. Try growing a plant without the 16 macro and micronutrients and see what you get (dead tree) or add N during a normal growing season and watch the results. You'll have more growth than you know what to do with (or, on a bonsai, more than you can prune.) The secret is to manage fertility based on the tree's needs. During the summer, higher rates of N will promote vegetative growth while higher rates of P and K will promote reproductive growth (flowering). Fertilization with N,P, and K later in the growing season is extremely important in preparing the tree for domancy. During this time, as days get shorter and cooler, the plant begins storing carbs for the next growing season. For this, N rates need to be reduced so little or no new growth occurs. You still want enough N for photosynthesis but not so much for growth. P and K rates need to be held constant so carb production is maintained. Once the tree is into full dormancy, fertilization can be stopped. All right, by now I've probably honked some folks off so I'll quit. *If anybody wants me to, I'll talk about soil fertility and especially availability and fertilizer form (i.e. organic vs. inorganic (they both have benefits, but a plant only takes up inorganic forms).