Parts needed for an Arduino watering project?

I have a Uno R3 and a collection of relays, shields and parts but I'm not sure if there is task specific shields and things that would make it more efficient.

If I want a greenhouse watering system, do I need a stronger or multiple arduino?

It should sense the soil saturation, and when it falls below a certain level, start a water 12v water pump (200 mA draw) to pump water through driplines for a set amount of time (instead of soil sensor hitting a certain level to make sure plants at end of dripline get sufficient water). If I want it to be wireless, and in a remote location with no power sockets, would a 12v 5 Amp hour battery work as a power supply? I'm a beginner with Arduino so any help would be appreciated, especially with the wireless aspect (bluetooth, "wireless", or wifi?)? Thanks!

2014-06-24T01:38:58Z

Oops, I forgot to add in that I wanted other sensors such as temperature, humidity, CO2 etc... so a wireless setup can transmit data back to my computer or I can remotely start the water pump when it's abnormally hot (which I guess I could automate with a temp sensor, but oh well). I found a transceiver module on ebay from china, but it's a one piece transceiver. Does it require another transciever to work or can it send data directly to a laptop?

?2014-06-24T00:38:20Z

I'm confused why you want it to be wireless. Your Uno will work just fine. connect the moisture sensor to the input, as shown in my site
http://www.skillbank.co.uk/arduino/index.htm
under measuring voltage (http://www.skillbank.co.uk/arduino/measure1.htm)

and control the water pump via a transistor as shown on the motor control page - third diagram down.
http://www.skillbank.co.uk/arduino/motor2.htm

A 12V 5Ah battery will drive your pump for 5Ah / 200mA = 5000/200 hours = 25hours continuous
(well not really, but say a weeks worth of intermittent use)
It will power your arduino for YONKS.

If your hygrometer is used continuously it will electrolyse the contacts, then it wont work well. I'd suggest using short lengths of copper water pipe for your contacts. Apply a voltage and measure the current. Take measurements at say 10 minute intervals so there isn't much current passed.

anything you dont understand get back to me.