8 Flowers You Should Never Buy As Seedlings

Hitting the plant aisles in big box retailers or paying a visit to your local garden center is a delight. But even more delightful is when you find petite plants looking cute in their tiny pots and retailing for only a few dollars. What a steal! But before you load them in your cart and rush to the cash counter, take a pause and consider whether you should really be buying these seedlings. Although growing starter plants has its advantages — you won't have to worry about germination, fret over being a little late in the season, or undertake laborious chores like thinning — it doesn't work for every plant.

Essentially, while some plants tolerate or even prefer transplanting, plenty don't. Sunflowers, larkspur, and nigella are prime examples. They dislike root disturbance and experience delays in their flowering, as they must first recuperate from transplant shock. And that's assuming their roots aren't wedged deep into their trays. In other cases, such as with poppies and cosmos, performance is far better using seeds versus transplants. For plants like zinnias and cosmos, buying seedlings doesn't add much value, as they're fast-growing annuals with a healthy germination rate. Plus, let's face it, seeds are cheaper! So, considering these myriad reasons, such as transplant shock, performance, and value, here are eight flowers you should never buy as seedlings.

Towering stalks, symmetrical heads, chrome yellow hues — what's not to like about sunflowers (Helianthus annuus)? But before you pick up some starter plants from the nursery, take a moment, since they might not produce the sunny sight you hope to revel in. Sunflower plants anchor themselves to the soil with taproots, and these guys are fussy. After having grown to a decent length, they — like a grumpy old man — feel displeased about relocating and express it by halting further development, at least for a while. Even after recovery, most plants only produce small flower heads. How disappointing!

Given that, it's best to sow sunflower seeds directly in the garden. Since they're pretty large in size, you can even involve your toddlers and watch their faces best the sunflowers after they bloom. Just bury the seeds 1 inch deep and cover them with soil. Check the label for spacing recommendations, so you don't have to thin the seedlings later. Look for pollen-less varieties, like ProCut Horizon (you can get ProCut Horizon Sunflower Seeds on Amazon), especially if you want to display cut flowers. They also have a high germination rate and bloom in under 60 days. That being said, if deer, rabbits, birds, or pillbugs visit your garden frequently to decimate seedlings, start the sunflower seeds indoors in a biodegradable pot, that way you can just plant the entire thing when you transfer it outside. After about two weeks of frost-free days, fully entomb the pot in the soil and put a bird netting on top (hold it down with bricks) until the plants grow 1 foot tall.

If you have ever wandered into a nursery looking for plants that help to keep away deer, odds are you landed on larkspur (Consolida sp.). Like any plant, larkspur doesn't have the power to send deer running for the woods, it also shouldn't get eaten, making this pretty native a great pick if you're dealing with deer pressure. While larkspur seedlings will certainly do their best for you and your area's hummingbirds, they won't match up to their directly seeded counterparts. Nursery starts fail to grow vigorously, and probably won't put out a full display of flowers. This is because larkspur doesn't take well to transplanting. They also aren't suitable for starting indoors in compostable pots, because they require cold stratification, which will occur naturally outside if you sow the seeds at the right time. 

So, considering these reasons, switch to direct seeding. Since larkspur seeds require cold stratification (exposure to cold and moist conditions to break their dormancy), sowing them about ¼ inch deep into workable dirt come early spring (or even in the fall before first frost) naturally improves their performance. To account for varying germination rates, put three seeds in each planting hole and thin the seedlings once they grow 3 inches tall. If they're happy, larkspur will readily re-seed, popping out in different parts of your yard, ensuring you enjoy the blooms every year without additional effort. But bear in mind that larkspur is poisonous and shouldn't be planted around kids and pets.

Finding blue flowers is so rare that once you spot them, as with love-in-a-mist (Nigella damascena), it's unthinkable to pass them up for another plant. After all, why miss out on the dash of tranquility and whimsy that their blue hues bring to the landscape? It also helps that their fennel-like, lacy leaves look striking even when missing the blooms, making Nigella a standout addition to any garden. Unfortunately, in their case, going the seedling route can be a big mistake. Like sunflowers, love-in-a-mist has a prominent, long taproot that gets easily damaged if it's forced to change sites. That's why, rather than buying their seedlings or, it's recommended to directly scatter nigella seeds on your garden soil.

Luckily, growing love-in-a-mist entails no rocket science. Since their seedlings tolerate frost, the seeds are often sown in cool summers or fall to allow for overwintering. This ensures the plants will green up early, producing huge blooms. Alternatively, you may lay them about ⅛ inch deep in spring soil. However, expect smaller blooms, albeit for a longer show. Note that these self-seeding flowers will effortlessly cover your backyard if you don't watch for volunteer seedlings and dedicate some time to deadheading.

Apart from their symbolic significance of honoring soldiers, poppy plants (Papaver) have become popular with gardeners because of their versatility — there are so many colors and bloom shapes to choose between, from the classic, bright red corn poppies to big but delicate Iceland poppy varieties. However, if you're looking for a spectacular show, avoid buying annual poppies as seedlings. Poppies have a deep root system, often requiring nearly 10 inches worth of soil to grow. That's why they tend to become root-bound in a nursery pot (or even when you start them inside, but delay transplanting). At that stage, there's nothing you can do to encourage the plant to resume growth. Besides, their roots don't take kindly to any kind of disturbance and perform poorly (assuming they survived the transplant shock).

So, do yourself (and your pocket) a favor and look for poppy seeds. Since they cannot germinate in the dark, broadcast the tiny seeds on an area with full sun. Also, as poppies appreciate sitting through freeze-thaw cycles, consider planting them in late fall, though early spring works as well. Some gardeners also have success directly broadcasting them onto the snow in winter. Although (depending on the variety and weather conditions) poppies can take nearly five months to bloom, directly sown plants always outperform starts, and are well worth the wait. Besides, if you allow the spent blooms to fade into seed pods, they'll return to your garden year after year.

Cosmos (Cosmos sp.) are a stellar addition to pollinator gardens. Both birds and butterflies enjoy their blooms, though you may be tempted to deprive them of a few to prepare your flower arrangements (watch for snoozing bumblebees though!). They even attract beneficial insects like syrphids to your garden, keeping pests in check. To enjoy these benefits, however, resist the urge to purchase seedlings from garden centers and grow them with seeds instead — even wildflower mixes will do. Although cosmos are grown through transplants and starts, they must be moved into the ground in under four weeks after starting under grow lights. Otherwise, they will become rootbound: Their roots will turn into a tangled mess and will be difficult to ease out from the pot. Not to mention, this will permanently impair their growth, affecting performance and stunting the plants. 

Cosmos are simply one of those plants that just grow, bloom, and perform better when directly seeded. Another perk? Cosmos flower seeds are quick and easy to grow for beginner gardeners – all you have to do is pick a sunny site and sprinkle the seeds in spring. Rake some soil (about ⅛ inch thick) to lightly cover them. Don't be too meticulous about spacing, as cosmos end up supporting each other when placed in proximity, and give the impression of a fuller bed. You don't even have to bother with amending the soil, as they grow lanky when fed organic matter. Expect the blooms in under 10 weeks.

Nasturtiums (Tropaeolum majus) are a gardener's friend. They sacrifice themselves to white cabbage butterflies and black bean aphids, protecting your precious vegetables. When not serving as a sacrificial offering, they adorn your garden with sunny yellow or orange flowers, keeping pollinators busy. If they're the rambling type, they even suppress weeds. Unfortunately, you aren't being a good caretaker for them if you choose to plant their nursery starts. Nasturtiums have fragile roots that are easily hurt by movement, which derails their growth and development. Put simply, they dislike being transplanted.

Given this background, it's advised to sow nasturtium seeds straight into the ground once the last frost is past. Don't worry, they're the kind of flowers that even the worst gardeners can handle, since they will practically grow themselves, do great in poor soil, and reach a considerable size. As their seeds prefer the dark, ensure they're buried about ½ inch deep. Although it isn't mandatory, steeping the seeds in a dish of water for a night before planting can improve germination. Alternatively, you can rough up their seeds with some sandpaper or a nail file to remove some of the hard coating before sowing. In case you've a short growth season and would like a head start, consider starting seeds in a biodegradable pot and moving it into the ground to avoid transplant shock. As nasturtiums are self-seeders, regularly remove their discolored blooms, unless you want them naturalizing.

Who doesn't love zinnias (Zinnia spp.)? They bloom colorful flowers that populate your garden with butterflies, hummingbirds, and bees. Plus, you can even make your own birdseed by growing these beautiful plants in your garden. They are easy to grow, too. However, you shouldn't buy them as seedlings, even though they can be transplanted (provided the seedlings are young enough). Zinnias are amongst those plants that naturally grow better when directly sown into the garden bed. Not only will this reduce any potential transplant shock, but this way, you can sow them thickly, which will create a dense, self-supporting stand. They are also rapid growers. Once you sow a zinnia seed, it takes under four days (though sometimes up to seven) to turn into a seedling. In other words, buying seedlings doesn't give you any significant leg up. Also, if you think buying relatively older seedlings will shorten the waiting time for blooms, remember the older they are, the less they will enjoy being transplanted and will need some recovery time before restarting growth.

So, how should you go about direct seeding zinnias? Once the temperatures hit 70 degrees Fahrenheit, sow the seeds about ¼ inch deep in the soil. Since you get many seeds for a fraction of the price (of seedlings), lay them thick. That way once the plants mature, they can support each other and absorb sunlight to their hearts' content, instead of badgering you for stalk support. Also, it only makes their display grander, given that zinnias are naturally profuse bloomers anyway.

Incidentally, 2025 is the year of the calendula (per National Garden Bureau) or pot marigold — and for good reason. With calendula, you can jump on the trend of "edible gardening," as their leaves and flowers can be harvested for salads and teas. You can also plant them to attract the good bugs that'll chase pests from your garden, especially the ones targeting your tomatoes. But don't try to get a head start on pest control by purchasing their seedlings. Although not as quick as zinnias, calendulas are nonetheless fast growers, and typically germinate in a week or two. Moreover, many varieties are ready to bloom in a month's time, though others may take around 50 days in total. So, buying seedlings doesn't make much sense on the cost-benefit scale.

It's easy to start calendulas with seeds, not to mention, a nifty way to introduce your children to your hobby (they will adore the C-shaped pips). Seed propagation is also recommended for USDA Zones 8 through 10. Because calendulas are a cool-weather plant, they can be sown in spring or fall. But make sure to fully cover the seeds with soil (about ¼ inch thick), or they won't germinate. Deadheading can help promote subsequent blooms, but if you leave a few flower heads to go to seed, your calendulas will probably self-sow and reappear somewhere in the garden again next year when conditions are favorable.