It’s beginning to feel like spring. The mechanical street sweepers, thank heavens, have returned. The Japanese witch hazel has given way to forsythia. The house finches are building nests. The daffodils the Charles River Conservancy volunteers planted last fall are beginning to bloom along Memorial Drive. Pansies are replacing the dead evergreens in window boxes and gardens all over the city. Even those of us who enjoy winter are ready for a little beauty and cleaner streets.

So it is serendipitous that a few interesting spring activities have sprung up, no pun intended. One is called landless gardening. All you need, says Laurel Valchuis, the 26-year-old creator of the concept, is two square feet of sunny space.

That sounds as if it might be possible for many downtown residents. The South End resident learned the technique in Tanzania, building gardens for people who needed accessible gardens growing more nutritious, affordable food than they otherwise would have.

Bostonians need the same thing. And many downtown residents have no land on which to garden.

Laurel uses a plain old burlap bag, a few rocks, and seedling-starting soil. She employs large yogurt containers or plastic bottles with the tops and bottoms cut off. After she pours a 1-to-2 inch layer of rock in the bottom of the bag, she uses the bottle or container to form a column of rocks in the middle of the bag, packing soil all around it. Then she plants holes in the bag with green leafy plants or other plants will smallish root systems. She waters the column of rocks once or twice a day, and harvests throughout the summer.

Last summer, she said, she had a really good crop of eggplants.

The bags can be placed on front steps, in a parking space, on a rooftop—anyplace where they’ll be protected from predators, mainly of the human variety.

Laurel, who grew up in Concord and has a degree in biology and ecology, will go back to school this fall for a research degree in community development and applied economics. You can go to her website, www.landlessgarden.org for detailed instructions. And you can order a kit from her for about 20 bucks that includes everything but the seedlings. Rocks and soil aren’t that hard to get, but burlap bags are no longer sold at many garden outlets, so you’d be stuck. This isn’t a commercial venture for her. It’s a labor of love.

Laurel recommends that you plant seedlings rather than seeds in the bag. She is starting her seedlings now for planting toward the end of May, but you can buy seedlings at many garden outlets.

Once you’ve got your burlap bag garden planted, you’ll probably need to clean up, and you can take a page from North Enders for that task. The North End/Waterfront Residents Association has come up with a new idea—Spazzare! The word means to clean in Italian. You may have heard of this imaginative campaign. They’ll attach brooms and dustpans to 11 trash receptacles in the neighborhood.

What newcomers and tourists will find surprising is that it has been only a few years that neighborhoods in Boston have had trash receptacles. Periodically the city would put them out, and just as periodically, they would disappear. But now the city seems convinced that Boston needs trash receptacles, at least along its commercial streets, and North End/Waterfront residents have taken that idea one step further.

Other downtown residents are going to be watching the North End and Waterfront to see how long the brooms last and if they make a difference.

Beacon Hill also has a new effort. Instead of focusing clean-ups on one spring weekend, that neighborhood’s civic association is on a mission to persuade every resident and business to clean up in front of their places all the time. All you need is your own broom, a dustpan and a green garbage bag.

If you like to meet people, the weekend of April 29-30 is the best time to do so. The mayor has designated those days as Boston Shines weekend, where everyone is supposed to go out and sweep like the dickens.

Efforts like these have often led to romantic outcomes, since working together is a good way to meet the love of your life. After all, wouldn’t you like a mate who has a lot of energy, is a good citizen, and will keep things tidy? It’s much easier to live with a person like that than the other kind. Any person participating in Boston Shines is likely to be that kind of person.

Good luck.