Open-pollinated kale seed, saved from the author’s garden, means one fewer seed packet to buy next year. (Barbara Damrosch)

I once had a friend whose garden stole his wallet and took over his life. Inspired by the great gardens he’d seen in England, he built a reflecting pool surrounded by brick-walled garden rooms. Soon the pool was dotted with waterlilies, the walls clothed with flowering vines and the rooms redecorated each year with high-maintenance flower beds, bursting with color. To my eye, it was money well spent.

Garden economics are tricky. They require an accounting system that measures not just the cost but also the gardener’s expectations, and whether they are met.

A neighbor who got into vegetable gardening to save money was dismayed that initially the money he and his wife spent was more than they saved on food, even though they were very competent gardeners. But she told a revealing story.

Yes, she admitted, they’d made hasty purchases as temporary solutions. Work and family commitments kept them from finishing their deer fence, so they’d used cheap plastic fencing until they had more time. But that came in handy later during a porcupine emergency. The ravenous creatures were destroying the raspberries and a precious pear tree. Surrounding both with the plastic fence saved the day. Similarly, a wastefully large roll of floating row cover, bought for insect protection, proved essential for creating a warmer space for all their young seedlings in chilly spring weather.

After a while, a gardener accumulates enough gear that new purchases become rare. But it takes judgment to get to that point quickly. Starting with basic tools such as a shovel, spade, rake, trowel and hoe is the first step, but only if they’re well made and just right for your own use — sturdy, but not so heavy that you come to hate to use them. Strong, well-attached handles are a must. You can probably put together the whole collection from yard sales.

In the years to come, you’ll be tempted by cheap plastic versions of basic garden stuff. Beware of flimsy plant supports and rickety little wheelbarrows. Easy-to-
assemble compost bins, raised beds and cold frames may be even easier for the forces of nature to take apart, whether they be wind, the expansion of icy soil or hungry bears.

Ticky-tacky greenhouses too small to hold much more than you and a few potted plants are rarely worth the price.

Some of these items might be useful in the short term, as the plastic fence was for my neighbors, but the structural integrity of solid wood or metal will outlive that of plastic and will age more gracefully. Plastic is unfixable when it cracks or bends, and ugly when its color fades in the sun.

Taking care of your equipment is good economics, too. I’m embarrassed to think of how many times I’ve left my spade or hand pruners outdoors and failed to tip my wheelbarrow against a wall so that it doesn’t fill up with rain. Bringing tools under cover after use, cleaning dirt off them and oiling them are all ways to stave off rust.

Seeds are not expensive when you consider what one seed will yield, and you can collect and save them for next year’s crop. Perennial flowers are costly but can be divided or propagated from cuttings to make more.

Gardeners are always choosing between time and money. If you must pay to have some of the work done, the quality of the food might still make growing it worthwhile. If you can do it yourself, it might save you the cost of weight training at the gym.

Ultimately, the most important principle of gardenomics is the balance sheet that nature provides. Left alone, a landscape will perpetuate itself, as plants and animals return to the soil in a fertile, self-sustaining cycle of life and death. If you turn your weeds, grass clippings and other organic wastes into rich compost, you won’t need bags of fertilizer. Make leaf mold by letting piles of autumn leaves break down, and you won’t need bags of mulch.

A new garden with poor soil might require purchased amendments, but by replacing the fertility you take from the soil each year, you will soon balance the books. You’re following a management system that’s already in place.

In the decades after he planted it, my old friend has loved his walled garden, as have the multitudes of visitors he has invited in. And my porcupine-plagued neighbor now says: “After gardening for a while, I know how many seeds I need. I’ve found out what works and what does not.” Both gardens have more than paid their way.

Tip of the Week

Faded rose blooms should be cut back to encourage robust reflowering in six to eight weeks. Wear thick gloves and long-sleeved shirts to outwit the thorns. Use the opportunity to remove any leaves that are showing signs of black spot, including yellowing. Pick up and bag the afflicted foliage.

— Adrian Higgins