Over watering can be a good possibility since that seems the biggest issue with newcomers to Bonsai. The soil should be allowed to ALMOST completely dry with just the slightest ting of moisture when you stick the tip of your finger (around the first knuckle) in the soil near the edge of the pot. A good temporary teacher for this is to stick a chopstick in the soil near the edge of the pot, check daily, and when the stick is dry its time to water. Learn to feel out what the soil feels like with the finger technique while using the chopstick and soon you will no longer need to use it.

Remember the relationship of rain to watering can some times be tricky and misleading when new to Bonsai. Just because it has rained does not necessarily mean that you do not have to water. The water has a tendency to role off the canopy of the tree and not hit the soil or do so sparingly, this is even more prevalent with more developed Bonsai as the canopy is more filled out (kind of like trees outside where you can stand under them and not get wet). That being said be sure to check the soil for its moisture content even when it has rained and if it does not feel or look adequately moist still water as normal.

Also be sure the soil mixture used is quick draining and drying and that the soil stays wet 3 days at most before drying enough to be watered again. Since during spring it may rain a lot, which in turn will keep your tree pretty much constantly wet, you will need to place your tree in a sheltered location (where it will still receive adequate light) where it will not be rained on, keeping the soil waterlogged.

As for the leaf burn issue that could very well be attributed to too great an exposure to sun, particularly if the tree has just leafed out and the leaves haven't 'hardened off' yet and are still soft and fragile. This can then be magnified if there is water on the leaves as it will magnify the sun rays affect on the leaves. Crab apples can be placed in full sun (more or less depending on the exact cultivar) but I have found a good number of trees that can be grown in full sun actually appreciate partial shade locations, receiving ample light in the early hours of the day and then being able to rest in the mid-day hours in the shade when the suns heat is the highest. I would at least keep the tree in partial shade during spring when it is still waking up and the leaves are fragile. As for outdoor location, I will also add that the south side of the house will be the best for light exposure.

Hope this helps

-Mike

thank you mike for the help. i think i will try the chopstick trick, see if i can get a handle on watering correctly. i, unfortunately, cannot use the south side of my house because that is basically just our driveway but i think the new location ive got it in now will be better since it does give it partial shade. again, thanks.