For anyone with difficulties kneeling in the soil, there are two useful options you might consider. I personally was delighted to discover these pieces of equipment after spending an entire spring
season doing all my plantings by laying flat on my tummy in the yard!
A kneeling bench, such as the Easy Kneeler is a versitle addition to your garden. It is a 20" high bench for sitting made of tublar stee. The seat can be flipped down into a lower position for kneeling and the legs of the bench become rails to help you push yourself up again.
There are lots of manufacturers of this type of kneeling bench, so shop around for one that suits you and your budget.
If you want to completely avoid kneeling and deep bending, you might want to consider purchasing a Scoot-N-Do or similar product. This 10" high seat on four wheels sort of resembles a childs wagon with the seat lifting up for storage beneath. Seated so low to the ground you can avoid kneeling or deep bending while still being mobile to traverse between your garden rows. There are also three-wheeled seats available; it is just a matter of personal preference as to use and what makes you feel most secure.