Here are some ideas about working in the garden, gardening equipment and preventative exercise to take care of your back for gardening.
Here is what I do, maybe some of it might be adaptable to your situation.
Essentially, never do anything cold, moderate what work you do, e.g. two half days rather than one full day, exercise carefully and regularly with your back in mind, and get some kit to help in the garden.
The idea is to minimise bending and excessive compression or extension of the lower back.
1) Buy or modify tools so you can work standing upright. I always use extra long handled tools, obviously I use my extra long handled tools in the garden and for concreting etc. I have had shovels modified by a local blacksmith & fitted with my extra long handles. Note/ the handles do need to be extra long to prevent bending, you have to be able to work with a straight back. It is a good idea to modify yard brushes and the brush for cleaning the car as well. The US style long handled spades that are commonly available, are only about 48 or 54 inches long (compared to 75 inches for the Standwell Long Pattern). The former are made in enormous numbers in China and are sold wholesale for a couple of dollars. They do have long handle compared to an English style spade but you will still have to bend and get used to the large curved shovel head, which is rather awkward in my experience and best for shovelling light materials rather than digging.
2) Buy a pair of work trousers with knee pad pockets and a pair of pads, e.g. Dickies range. I find these essential for almost any gardening or DIY task or even housework. I avoid pads that fit around the knee I find them very uncomfortable after a while and they tend to slip off. With the knee pads it is easy to get up & down on one leg at a time, if necessary use the spade for support. If I am lifting stones into a wheel barrow, I always get down on one knee, lift the stone onto the flat thigh and go from there.
3) In winter, also wear full overalls and a body warmer over it (one of the workmen type with lots of pockets is very handy), even if it makes you sweat, keep your back warm.
4) I use a garden trailer rather than a wheel barrow to avoid lifting and moving the heavy weight of a barrow if full of soil or stones. If I am going any distance I attach it to the old lawn tractor.
Before you start digging, pootle around a bit finding & cleaning tools, walk around and muse before digging, just to warm up. As far as possible, never lean forward to lift even the lightest object. Always get on your knees to weed and plant, if not swing your non-supporting leg out backwards in a ballet pose to pick up light stuff. When kneeling, if possible support your trunk with one hand whilst planting or weeding with a hand trowel.
Read the operating instructions for your Standwell Long Pattern Spade.
When I was at school, exercise was called, "Games" and playing a foolish game is the best way to approach exercise as far as I am concerned. However, back pain & ageing knees have curtailed those pastimes so I have a much less strenuous regime of exercise I carry out every day to keep mobile. This is my regime - you must adapt as you see fit, always be cautious until used to an exercise. I do not always carry it out perfectly; especially as Ruby our Jack Russell is usually jumping all over me.
Daily exercise starts under the duvet where the back is supported and warm.
i) Tread alternately for a few minutes, as if pushing down pedals, to get the hips loose.
ii) With the soles of the feet sliding on the sheet bring knees up alternately for a another few minutes which gets the circulation going. Hold the knees alternately in both hands and carefully pull in towards your chest to gently stretch.
iii) Do a number of very soppy sit ups just raising the chest a little, this feels as if it is warming up the lower back and stomach muscles. Be wary about sit ups, I never do them as taught by the games master which seems unnecessarily strenuous and bends the back rather alarmingly.
iv) Loosen head and neck muscles by raising the head & moving it side to side.
v) Carefully stretch arms over the head and repeat the first exercise.This has helped a lot with sciatica.
vi) Sit up slowly, grab nearby track suit & socks and put on whilst lying back on the bed. Sit up & stretch arms and shoulders slowly and carefully. Hang from rafter (or chin bar in door way) for as long as possible to stretch back, again very good for sciatica. Do a few chins.
vii) Onto my hands & knees. I now do the silliest exercise, wagging my hips from side to side until all feels loose (the terrier likes this one). Loosen head and neck muscles, raising head and also side to side. Do a number of press ups off knees-a straightforward press up off the toes strains the back.
viii) Take the dog for a walk, just a mile or so, try to walk briskly on the way back.
I find this can happen with almost no effort on my part, that sharp flash of lightning like pain right across my lower back.
I lie down on the floor in front of the fire with an ice block under my back (outside of my clothes) and don't move for many minutes until the severest pain has gone. I get up and try to walk around periodically but sometimes I might have to spend most of the day in that position. When things have calmed down a little, maybe next day, I alternately warm my back with one of those bead "hot water bottles" heated in the microwave. However, I more often use the ice block and take one to work with me as sitting all day seems the worst thing.
Standwell Tools, Derbyshire, England. email: email@example.com phone: 07779 169 792