How to Grow and Care for Nasturtium
There's a lot to love about nasturtium, an unfussy annual originally native to South America that blooms just about anywhere. Nasturtium comes in two primary types: trailing (Tropaeolum majus) and bush (Tropaeolum minus), explains Jon VanZile, a master gardener and author of Houseplants for a Healthy Home ($16.44, amazon.com). The best part? The most common versions of "nasturtium leaves and flowers are edible and make a lovely garnish," shares Megh Wingenfeld, a home and garden creative who enjoys adding them into salads and butter. VanZile agrees, but suggests using just a pinch, since nasturtium has a pungent peppery taste.
While nasturtium really is easy to grow, it does require some attention. To ensure a charming season-long display, our garden experts share how to plant and grow nasturtium, ahead.
When to Plant Nasturtium Seeds
It's hard to imagine that nasturtium's "disc-shaped, slightly circular leaves with smooth margins and cone-shaped flowers" start from brain-shaped seeds, notes VanZile. And since Nasturtium seeds germinate rapidly, "there is no need to start seeds indoors early if you aren't able to," adds Wingenfeld, who recommends "direct sowing them into the ground whenever you start your garden in the spring." You can do this even during mid-summer; "you may see sprouting in just two days!" Wingenfeld shares. Overall, nasturtium is inherently a warm-zone plant (it thrives in zones 10 and 11), so it's best to get seeds into the ground two to three weeks after the last frost, adds VanZile.
Since nasturtiums grow best in day-long full sun, it's best to start with a well-lit location. And if this negative space also falls at the edge of your garden, even better: Nasturtium is known to effortlessly fend off garden pests like deers and aphids (thanks to its peppery taste), which means it can play defense.
To pick the best nasturtium type for your garden, consider their mature size and your property's layout. For example, trailing varieties require ample space to sprawl, while Jewel species (a more compact version) do not, Wingenfeld and VanZile affirm. Ultimately nasturtiums come in dozens of variegated types and colors, so they are easy to scout and pair with "companion plants that don't need a lot of water or fertilizer," notes VanZile. But, "if you're growing a climbing or trailing nasturtium in a regular bed, you may need to provide support."
For the best outcome, always "direct-sow nasturtium seeds into holes about a half-inch deep, spaced about a foot apart," shares VanZile. And if you plan on buying and transplanting potted iterations, proceed carefully—their fragile roots do not transplant particularly well, VanZile says. To set these plants up for success, water them regularly (but moderately), as "nasturtiums are somewhat drought tolerant and don't appreciate soggy feet," Vanzile says. He also recommends using a blooming fertilizer to encourage a greater yield and larger-sized blooms. But, avoid providing excessive nitrogen—an element that, although guarantees beautiful foliage, will result in fewer flowers. Lastly, to ensure nasturtiums remain bright and lively all season, deadhead them often, and "don't be afraid to harvest vines deep in the plant. They will grow back quick and stay looking fresh!" Wingenfeld shares. Anytime "you notice wilted flowers and old leaves or vines, just remove them," adds VanZile. Doing so encourages dense growth and a better presentation.
Since nasturtium is easy-going, it's happy to grow in virtually any container or planter (providing you follow the same rules mentioned above). Approach planting seeds in containers in a similar way: Place each one at a depth of half an inch and water them lightly when you're through.