How to build Arduino+XBee 1km link ?

How to build link ? Solar power+ Arduino + Xbee+ ds18b20+ moisture sensors and other side web log server. I want to put arduino to the greenhouse measure temp. and moisture and send this data over air to web log server. What I need ?

Sorry my english.

What I need ?

The right XBee, with the right power, range, and antenna style.

I don't think you're gonna find XBees - at least 2.4 Ghz transceivers - with 1 Km
range, even if some websites claim to get it. Usually, those claims are off by about
10X in practical use, from my experience. You might look for something with lower
frequency, maybe 433 Mhz, and a lot of transmit power, maybe 1 watt, and some
nice highly-directional antennas.