Maybe it is this year and the drought but I think that you can have a great deal of garden if you have some kind of automated watering system. I have a pretty big garden but minus the watering I think that 30 min would more than cover the dead-heading and weeding I need to do.

My other piece of advice is take your time building the gardens and working on your plans. If you do this you can easily find a balance I think.

and are you getting older or younger? That will make a difference as increase your gardens expotentially. I have a 12 year old garden and I am 57, nearly 58. What I need is a well and a watering system. Now, that would be worth a home equity loan. And if you dig a well for about 5k, you'd have your money back in not too many years. Given the price of water, if it's city/town/Quabbin that's worth holding off on two gardens.

How much time your gardening takes is at least partly governed by how you garden. I have a few beds that have highly organic soil and are well mulched and edged to severely reduce the need for weeding or watering. They have bulbs, low-maintenance perennials, shrubs and vines. Those beds only need a few hours of work annually, and they get attention every couple of weeks at best. I have woodland shrub beds that I mulch every couple of years and take the weed whacker to for trimming back undesirable plants a couple of times a year and they are done. I also have perennial/shrub mixed beds closer to the house that have plants that need more attention. These beds have the plants that need dividing, deadheading and more attention for bugs or disease. My kitchen gardens tend to need the most attention and also are close to the house for easy use at mealtimes. As I continue to get older, the more my new gardens are low maintenance since I know that my energies and abilities will wane over the next few decades and I don't want to have to rip out gardens that I love. On the other hand, it's not too hard to simply mow and seed to grass a perennial bed that you have decided is just too much to maintain.

My advice would be to have an overall plan, at least mentally, and then work on it over time as you have time. If you put it in all at once, it will eat up your daily half hour at the expense of your already present gardens. It also won't allow (as easily) for impulse plant buys and changing tastes over time. At least for me, my gardens will probably never be finished as long as I'm still able to lift my spading fork.

What an interesting question! It's such a personal matter, almost impossible to answer in an objective way.

The plants in your gardens DO also dictate to some extent the time needed to tend to them. I prefer plants that don't require a lot of fussing - deadheading, regular dividing, cutting back, etc. I recently bought Tracy DiSabato Aust's Well Tended Perennial Garden, just so I could keep track of what I am not planning to do! OK, my monkshood is 5' tall and blooming like mad right now, and she probably would not approve; I can live with that, because I love the wild color and the untrimmed form (not at all her ideal compact shape) in my late season garden. The self-sowers, like verbena bonariensis, nicotiana and eupatorium sometimes seem to have the upper hand, and passers by may wonder if there's a gardener in the house at all any more, or if I've moved away.

You're probably smart to be considering in advance how much extra time each new square foot of garden will cost, but you also need to ask whether more garden will give more enjoyment and whether it's worth that extra effort. This can't be answered on a square foot basis at all.

Personally, although I am getting really old, really fast, (LOL, Marie, you are too funny!) I enjoy breaking ground, and there are many, many, many more fascinating plants I need to try while I can.

Having a master plan is a great thing, but beware of too many small garden areas dotting your landscape. Have you considered widening the 5 x 60 bed to make it closer to the 2/3 or 3/4 ratio that is considered the "aesthetic ideal"? You could easily double or triple your square footage without seriously impacting your time investment, since the weeds tend to appear much more regularly (and need to be removed more quickly) in the front of beds than in the back or middle ground.

I'll admit that I am sometimes overwhelmed, and sometimes there is no dinner for days on end when I'm in a planting or weeding frenzy. But the point is that I love every minute of it, and would not be happy with less garden or more lawn. When you reach your ripe old age, will you look back and wonder how much more you might have done, or will you be satisfied with what you have and glad about the control you exercised in limiting your gardens? That is not a question that can be answered based on square footage, it's just a question of personal style.