First, are your plants indoot or outdoor?
For the outdoor variety, set up an H2O drip or low spray system with a timer. Make sure you know what timing your plants like. Set the timer for early morning and/or evening watering. FEED your plants the day before you leave, do NOT Overfeed, more is not better in plantland.
Drip systems need to be customized for each situation... the basic supplies with instructions can be found in the garden or seasonal area of many chain stores, such as Wal*Mart, Lowes, and other lumber yards or large retailers. Smaller Garden Shops should also be able to help.
With most plants, a week is not critical for feeding as long as roots can access moisture.
For INDOOR plants in general, turn heat down in summer, then acquire a water bulb, this is designed to slowly release drips of water when inverted and placed in soil surrounding plant(s). If you have a trusted nearby relative or neighbour, ask them to look in from time to time to ensure plants look good and are not drying out unexpectedly. If you are not comfotable with someone coming in, hen see if you can find plantsitter to whom you can take your plants for love and care.
Remember, we all can be fallible, so it is nice to have someone backstop even the best of plans. By the way, think about making your water system permanent, then it should be a no-brainer the next time you go away.
Hope this helps...
Brian Coldwells,
The Country Coldwells
Merritt, Canada