I would consider myself an avid, yet accidental gardener. I pretty much grow what I like and use, but apart from designing low key, easy grow vege beds, I pretty much go with the flow. Last year, I harvested a whopping 20 to 25 kg of tomatoes ... of just 6 or 7 plants!!! The biggest fruit weighed in at over 800 grams.
My colleagues asked me what my secret was - and I confessed I had none. I simply mixed top soil with compost, added some sheep pellets et voila. The tomato plants grew and gave me a huge amount of produce. This year, they look a hit average. I just brought in the first handful. On the other hand, I picked 800 grams of bush beans. Last year, I had maybe a dozen beans in total.
So what's the "secret"? The weather, plain and simple. My lettuces went to seed early this year (and I just put new seedlings out), the tomatoes didn't like the early heat wave and despite getting battered by a storm last year, they did thrive as they wanted cooler, wetter weather first and the heat after. This year it's hot, cold, hot, cold, now that it has been wetter the last couple of weeks, the poorer seedlings have recovered and thrive, whereas the three early great starters of my tomatoes look like rubbish.
So if you're like me a bit more experimental, easy going and laid back when it comes to gardening: don't fret if one product doesn't get you an award winning crop. Enjoy the ones that prefer the current conditions. That way, each year, each season will be a surprise ;o)