This guy is spot-fucking-on. Do not buy or rent a pressure washer for this, it's complete overkill.
Bleach+water mixture in the spray canister they linked is perfect. Instead of a scrub brush, I'd recommend getting a gutter blaster of some sort. My local Aldi was selling one similar to this a few weeks ago. It's like a mini pressure washer.
Just make sure you wear eye protection when spraying your house down with the bleach/water mixture. If it's windy it can sprayback into you. Wear white clothes or clothes you don't mind getting bleach on. But this is 100% the way to go, just cleaned my house the same way and the bleach just eats that mold right off. Super super easy.
I'd get one of these: https://www.amazon.com/Valterra-A01-0187VP-Flexible-Tank-Wand/dp/B000BGHYE8/
Flush with the tank open, and as others have said, you'll need to fill it some and let it sit between flushes to soften things.
If you don't have one already, there are clear sewer connectors that will help see what's coming out while flushing.
Drip system is like a hose, actually it will connect to your hose, it's not needed but it's really nice and will help watering properly. If you go straight hose get a wand that diffuses the water out so it's not a hard stream, like this and water in the am.
Tomato's like the be burried deep, I always plant mine over the first set of leaves.
I would stay clear of cucumbers and squash, they produce a lot but they also take a lot of room. Try salad, radishes, etc.. find a planting chart for your area and plant what is time to plant..
I worked at a nursery in a small box hardware store and these were the only nozzles that lasted any amount of time with hard use and multiple times a day watering.
Orbit 58543 Telescoping Gutter Cleaning Wand https://www.amazon.com/dp/B00CLOG5MK/ref=cm_sw_r_cp_api_fabc_C-0QFbNQB808F
You can do this yourself if the gutters are accessible. The pressure from the wand will blow the sludge out down the spout
Water pump and watering wand.
Orbit SunMate Hose-End 56098... https://www.amazon.com/dp/B004Q48RW4?ref=ppx_pop_mob_ap_share
VIVOSUN 800GPH Submersible... https://www.amazon.com/dp/B07L54HB83?ref=ppx_pop_mob_ap_share
Hose and clamps not included.
You can get a wand that attaches to your hose to make routine cleaning a bit easier (no ladder if you're a single story). I have a huge assortment of trees from gums to pines to maples dropping all sorts of stuff throughout the year.
If money is no object, the Haws 24 inch watering lance ($115 on Amazon) will last a lifetime as long as you take the simplest of precautions such as not driving over it.
I've lived for a year at a house surrounded by Douglas Fir trees. My advice is don't bother with any of the gutter guards. One I tried (green plastic triangle shaped ones) actually made the problem worse.
And get one of these - https://smile.amazon.com/gp/product/B00CLOG5MK