Here are some of the items you might need:

Sunhat(s)

Sunglasses

Sunscreen

Bug Repellant

Pocket knife

Work gloves

Water vessel/thermos

Allergy medication

Sleeping bag, pillow

Old clothes that WILL get dirty (seasonally appropriate)

Over-alls

Work boots

Rain boots

Rain jacket

Warm underwear and outerwear

Thick work pants

Cool long-sleeve shirts (old collared shirts are great for this)

*Try your local Sally-Ann for many of these clothing items!

Recording book (for all of the information you will be learning)

Hobbies (books, running shoes, musical instruments, journal)

*Talk to the farmer about your gear. They might be able to provide you with some of these items, and there may be particular items you are required to bring depending on the kind of farm they are.