As to the yellowing: are they getting enough water? Is it your Winter?

No, don't cut back the green fronds as they are feeding the roots with sun-produced nutrients. I'm not sure when your winter is... if any at all... but you could cut the fronds back then and fertilize. I'm not all that knowledgable about growing asparagus in a tropical climate; perhaps someone else will be.

Thanks Kate. I am wondering as well if it could be a lack of water. We will try giving it some more.

The thing is we never have winter, so need to determine after how many months of foilage to finally cut back and start my first, albeit small, harvest.

Ummmm... your plants are fairly young to produce an eatable crop. You can usually start harvesting after two years... possibly one year, but just a few. I'd leave the fronds on for at least a year, and just cut off those that get old and die. When you start seeing growth where the stem is about as big as your baby finger then you know that you can start to harvest. The spears will get larger as the plants age.

Is there an Agricultural Station in your area? They might be able to answer your questions specific to your area.

Thanks Kate. When it is finally time to harvest, should I cut all the way to the ground or do I leave 1/2" of stalk? Also, after I cut everything, I should cover in compost and fertilize?

There is a nursery here, but they are fairly new to asparagus. As such, wanted to seek additional advice.

Check to see if your county has a Master Gardener program. They may have a help desk or an email address where you can send questions. Meanwhile, here's something from Master Gardeners of Orange County, Ca. http://mgorange.ucanr.edu/Edible_Plants/?uid=154&ds=530

Igteacher: this poster is in South America in a tropical climate.

salevene: you cut them to the ground or even a bit below. Once again, I'm not sure what to tell you in your climate about cutting back and fertilizing. I think I'd be tempted to use an organic liquid fertilizer several times a year as opposed to compost once a year.

I actually wonder if you will ever need to cut back the whole bed to the ground or just use what comes up as new growth. The severe cutting back has more to do with our freezing winters and the need to clean up rather than any actual plant need. But, a severe cutting back will give you a larger crop rather than the occasional spear. I guess growing asparagus in your climate will be an experiment.