Mistakes Gardeners Make When Transplanting Seedlings

Whether lovingly nurtured on your windowsill or thoughtfully chosen at the nursery, seedlings embody a world of promise and hope for a beautiful garden. But to ensure they stay true to their promise, they must be given ample care. Unfortunately, despite the best intentions, many gardeners make critical mistakes while transplanting their seedlings into the garden soil. This sets up the younglings for poor growth or downright failure, pouring cold water on all your spring garden dreams.

So, to prevent seedlings from dying and to ensure your time, money, and effort aren't for naught, we contacted House Digest's Garden Editor and in-house Master Gardener, Tiffany Selvey, for an exclusive interview. "There are a lot of small mistakes gardeners make when transplanting seedlings that lead to big problems," she tells us. The short of it? Avoid making mistakes like ignoring the hardening off process, siting the seedlings in dry soil, and spacing them too close to each other; otherwise, be prepared to handle bigger problems in the future. 

So you followed the best way to start seeds indoors, and the seeds have germinated soundly and grown their first pair of true leaves. With the frost danger long past, these seedlings are ready to move into the garden, right? Certainly, but not without undergoing hardening. In her exclusive chat with House Digest, Tiffany Selvey explains, "For gardeners who are transplanting seedlings they started indoors, skipping the vital step of hardening off those little plants before placing them in the ground can be detrimental." Essentially, hardening off is the process of adapting the seedlings to garden conditions.

"Seedlings need to be slowly acclimated to the outdoors before moving to their final destination," elaborates Selvey. That's because once in the ground, they must withstand adverse events like strong winds, heavy rainfall, intense heat, temperature dips, and pests, which they did not encounter indoors. By hardening off plants, you give them an increasing amount of exposure to the natural elements so they become stronger. So, around two weeks before transplanting, start exposing your seedlings to the afternoon sun for three hours. Raise the exposure gradually every day, except when it's windy. You can skip this process for nursery-bought seedlings. "If you're buying seedlings, they should already be hardened off and are ready to plant," advises Selvey.

Not preparing the soil before giving your plants their new home is another mistake you can ill afford to make. Aside from loosening the soil so that the roots have a higher chance of cementing themselves into the ground, you must ensure it remains moist. "The soil around seedlings should be kept consistently moist until they are well-established — at least a few weeks," states Tiffany Selvey in her exclusive interview with House Digest. "These young plants have small root systems, but the larger the plants grow, the further their roots can reach for water." This ensures the small roots find their footing quickly and resume growth without any further delays. Aim to water the ornamentals and veggies every other day, particularly through desiccating winds and excessive heat. Also, soak broad-leaved seedlings in greater amounts of water to account for their needs.

Selvey also reminds gardeners to be mindful of plant spacing. "When you're looking at your little seedlings, it's hard to imagine how large they will get quickly. This is particularly true for large annuals like tomatoes and squash," she says. "It's important to know how big your plants should reach at maturity and space them accordingly to avoid disease issues later in the season." Fortunately, seed catalogs have you covered, as they list the spacing requirements on the label. Make sure to follow the "greater spacing" requirement so that the plants can fill out the space without overcrowding. Otherwise, without proper air circulation, the foliage will remain wet and become vulnerable to fungal diseases later in the season.