You can basically use most of your standard staff techniques with a hoe without any problems, and have the added bonus of utilizing the metal piece for both strikes and control depending on how practiced you are at hooking things.
A good rule of thumb when looking at farm implements is to assume that just about all of them can be (and have been) used as self-defense weapons at one time or another. This includes the hand scythe, kama, and sickle. Your standard issue farming scythe is actually an outlier and that’s because it is awkward to handle from the way the blade positioned. The war scythe itself were made when farmers took their scythes to the local blacksmith and fitted it so the blades pointed up rather than sideways like a standard issue polearm. Any farming implement with a straight pole like a hoe, a pitchfork, a shovel, or even a broom easily transition. This is because of the pole itself; when the farming implements are removed it’s just a wooden staff.
Staves are among the easiest weapons to learn, and the techniques feed directly into the more advanced longarms like the spear or halberd. You can and often do make use of both ends, switching between them in a diagonally crisscrossing pattern.
So, if you had a shovel, you could roll it over and use the head to attack your opponent’s food (stabbing downward) then either bring it back to strike again with the head or simply roll it over as you advance to strike high with the wooden butt then on the step back to strike their ribcage with the shovel.
One of the problems for beginners and those who’ve never worked with weapons is understanding that you use utilize more than just the blade when you fight. The entire weapon actually gets used. With staff weapons, that’s both ends, and the hands transition up and down the length of the weapon to create a distance advantage over your opponent. You can hold it at the middle to strike or at the furthest ends. This creates a flexible combat style that transitions easily to a multitude of improvised weapons.
When your looking to adapt a household or farming implement into a weapon, its important to think about the actual movement set associated with it. How it moves dictates how it will work in a fight. The hoe’s design leads to sweeping motions, driving down (like you would into dirt) or up (in the opposite direction) because the bladed part is horizontal to the staff. However, because of the hook, one might (theoretically with Jackie Chan-esque ingenuity) be able to reach around behind the head and twist to achieve a makeshift throw.
In answer to your question, the hoe wouldn’t be out of left field as a weapon choice if your character was in the garden working and got attacked. Most gardening tools can also double up as improvised weapons as needed. Depending on your character’s temperament, weed killer can easily become a means of chemical warfare. Also the hose.
The scythe really is the odd man out.
If you want to run with the idea of improvised weapons, I really recommend intense studies of Jackie Chan for choreography ideas with special attention paid to his Chinese films.