It might simply be a matter of location that causes failures of certain plants while others thrive.
Our watermelon plants get full sun for the whole day, they do far better than when we had them planted in an area that was shaded in the late afternoon.
Tomatoes are another plant that wants all the sunlight it can get and that means they are going to be very thirsty as well.
We have been growing tomatoes in
organic straw bales for several years now and as long as rains don't drown the plants early in life, they produce bushels of tomatoes all season long.
(this year was the first time our plants got drowned all spring long and they didn't do well because of it)
Our biggest issue is insect damage, this is something that we southerners have to simply deal with since we have such a long growing season. (End of March to the end of November or mid December)
Check your sun hours first, then check your soil (if you are growing in ground) there
should be lots of fungi in the
garden bed, lots of worms are a really good indicator of your soil's health profile.
Organic matter in the soil is also key, many writers want under 10% organic matter, I prefer to try for at least 20% organic matter in my garden soils, organic matter supports the microbiome life forms we have to have present for the best plant growth.
"Cide" remediation is done with large quantities of fungi and bacteria,
compost is the "usual" method of increasing these organism numbers regardless of what you want to grow, more microorganisms is usually a good thing.
Cilantro likes partial shade, when it grows in such sunlight hours it won't be quick to bolt. (Cilantro (coriander) doesn't like to dry out, when that occurs the plant will "bolt" because it feels death coming on and must make seed for the species to survive.
Keep at it and you will succeed.
Redhawk