What am I doing wrong with my coffee tree?

My coffee tree grows fine but loose and gets lots of yellow leafs and some with holes in. It grows in normal bagsoil blend with perllite and lots of bark pieces.

I water it with tapwater, but where I live the water should be pretty soft. Is rainwater for this plant important? It is situated light but not in direct sunlight. Im pretty sure I do not overwater it. Fertilizer only now and then, not often.
Not sure what is happening, I would love for it to get dense and dark green as its supposed to.

This message was edited Sep 9, 2013 11:53 AM

The hole I see in picture 2 looks like mechanical damage. Either a bug ate it, or an accident happened and the leaf perhaps got cut or something. If this happened while it was still tight in its bud it would not take much of a cut or a bite to damage the leaf. So look all over the plant, and in the top layer of soil for a pest, if there is one there is probably only that one, so get rid of it.

The yellowing leaves could signal 2 things. The first might be nutrient deficiency. Read the label. Are you using a product with N, P, K and trace minerals?
The other possibility is over watering. Older leaves turning yellow, falling off is typical. When you water, is the plant starting to dry out some? (easy test: Lift the pot and test the weight right after you water, then do not water again until it feels lighter). Coffee plants do not want to go very dry between watering, but they do need some air in the soil.

I am using the most typical plant nutriant here in Denmark, so I guess it's ok. I'm not quite sure what N, P and K is in danish. Im pretty sure I do not overwater it.

Just checked the label. It has got npk and minerals. But it has only gotten very few waterings with nutriants. Maybe I should do it more consistently in the spring/summertime. And I will gather rainwater from the garden. I really want it to thrive.

N = Nitrogen. Plants use this to grow green leaves. Often in the form of Nitrate (NO3) but can also be in other forms, such as urea.
P = Phosphorus. Plants use this to grow roots and flowers. Almost always in the form of phosphate (PO4, I think)
K = Potassium. Plants use this for maintaining water balance. Usually just listed as potassium, it is often in combination with something else.
Deficiency in any of these 3 can cause slow growth, pale leaves, often yellow.
Plants need more of these three elements, so fertilizers are usually labeled with the amounts of each.

All the other minerals may be called trace minerals, or micros.
Iron, Magnesium, Calcium, Manganese and several others. Often Iron will be specified, and plants need this in enough quantity that it is worth looking for. (Your plant is not showing iron deficiency).
Plants need the rest of the minerals in much smaller amounts.

In the USA fertilizers need to be labeled with how much of each N, P, K and other nutrients are in there, and the sources.