Here are some tips and tools for the Senior

Gardener, depending on abilities:

Use raised beds, boxes, or flower pots at a convenient height to garden from a standing or seated position.
Place garden pots on plant caddies for easier movement of pots and plants. Bring the pot to a seated person to work on.
Use tools with built-up handles for a better grip, or wrap and secure foam around smaller handled tools. Look for tools until you find the right ones that will work.
Use smaller, lighter weight watering cans for watering. See this post on Easy Garden Watering Tip.
Use watering wands which are long-handled watering tools for easier reach.
Long-handled tools also make reaching easier. Try to look for lighter weight tools as well.
Kneeling pads give knees a cushion from the hard ground.
A sturdy footstool makes a chair nearer to the ground, but make sure your loved one can get up and down.
Use gardening gloves to protect hands from injuries.
Use hats and sunscreen as needed to protect delicate skin from the sun.

For a list of garden tasks, see Get Moving in the Garden.