What's the biggest mistake that actually made you a better gardener?

One of my biggest gardening mistakes was planting my first vegetable garden far too early because I got excited by a few warm spring days. I hadn't paid enough attention to the average last frost date, and one cold night wiped out almost everything I'd planted. It was a frustrating lesson, but it taught me to respect my local climate and be a lot more patient. What's the biggest mistake you've made in the garden that ended up teaching you the most?

My biggest mistake was letting ants destroy my whole purple hull pea harvest.

I now know I could have killed them with vinegar (or used dishwater) and saved the harvest.

Mine was more a stroke of luck. We have a garden tractor with a tiller attachment that would not start a few years ago. This led me to a minimum tillage, soil building method of gardening and the results have been fantastic. I now do cover crops between plants and rows and build soil. Churning soil into a fine powder with a tiller is the worst thing possible, the garden tractor sits quietly today.

I don't think I've made the biggest mistake yet, but this century is still young, so who knows. I make a lot of little mistakes that I consider learning opportunities. I guess a biggest mistake would be one where my entire harvest is decimated--luckily I haven't had that one yet.

If I had to list a biggest mistake so far, it would be trying to garden with a preconceived notion of what a "proper" garden should look and feel like; based on images and text of neat rows of crops. As a beginner gardener I was lured into that fantasy that a mini-monoculture would be easy and neat and, the notion of "oh just how hard could that be." My impetus to getting onto backyard gardening in the first place was to grow my own food free of any poisons or artificial fertilizers. I wanted to grow food as our forefathers and mothers did; naturally, and with compost I made on my own. The pests put stop to that notion fairly quickly. And this is where a lot of people probably give up and revert their garden back to lawn.

Well, I'm persistent, and in looking for solutions to naturally attack the myriad of pests that where attacking my plants led to sites like permies, and others. I am determined to grow food uncovered, and unsprayed and I'm slowly getting there. Every year I plant more plants, and create more structures that bring in beneficial insects to balance the pest populations. I am now planting as many, if not more, flowers and other plants to attract beneficials as I am food for myself. I plant to not only bring in the beneficials, but some of the pests they need to eat in order to come to my garden in the first place. For example aphids are needed to attract beneficials, like lady bugs and lace wings, that eat them. Some aphids only eat certain plants, like the Oleander aphid, it attacks plants in the dogbane family, such as milkweeds. Oleander aphids don't eat my brassicas. Some Aphid eating beneficials will eat many types of aphids. If I can attract aphid eating beneficials to my garden with plants I don't eat ( trap plants ), then when the brassica eating aphids show up, I have an army of predators waiting to devour them before they set up camp.  

Oh, I see I've gone down a rabbit hole. hehehe. Have fun with your mistakes, they can spawn lot's of learning opportunities.

Not labelling my seedlings properly the first couple of years. I was so sure I'd remember what was what, and then a month later I've got 40 pots of identical-looking brassica seedlings and absolutely no idea which are the cabbages and which are the kale. Now I label everything obsessively, even the ones I think are obvious.

As for specific mistakes, read this one carefully and don't do what I did:

One of my neighbors had horses and a small hill of horse manure that he volunteered to help me dump into my garden.  I did.  The following season only one type of plant would grow to the exclusion of others on the exact 1/4 portion of my 1 acre garden that we had spread the manure.   I destroyed an enormous portion of my garden because of the fact that the digestive system of horses did not destroy the herbicides that were obviously sprayed on the hay that his horses had eaten.  Beware of what you put into your garden to "help" it.  I'm sure you can imagine how much care I put into my own composting for my gardens now.

Non-specifically:

My biggest mistake was moving too quick.  When I started I simply purchased as much seed in as many different types of vegetables and associated plants, and put them in the ground and wrestled with them until I "won".  Now I have learned to slow down and get to know each variety of each plant well.  I learned to make sure that I get the exact variety for my exact location and my exact soil.  Taking the time to get to know what I'm working with and then working with it until I start to feel like I'm in a position to add to the conversation with regard to making recommendations about each variety; or not.  I can go on and on, but I'm sure you're getting a read on it.

Hello
Someone offered lending me a land for doing Permaculture. I Said yes because it was free but i wouln't do it again. Why ? Because it was 3000 m2. Too big for beginning even with woofers !!  Cheers from France. Julien