Avoid These 7 Common Transplanting Mistakes

You may think transplanting is as simple as buying a tomato or petunia seedling, digging a hole, and planting it in the ground. And while this may lead to a healthy plant, plenty can go wrong during this process, leading to stunted, discolored, or even dead plants.

Whether you buy a seedling from a garden center or start your own seedlings at home, it’s disappointing to watch your plants go from healthy to unhappy. But don’t worry, you may be able to save your sad plants.

I’ll cover some common transplanting mistakes so you can avoid making them yourself. Plus, I’ll describe what actions to take if you’ve already made one of these errors.

What Is Transplanting?

Whether you want to grow flowers, vegetables, herbs, or another type of crop, you have two main options. You can direct sow seeds outdoors in the garden or transplant seedlings that you’ve bought from a store or started indoors.

Roots like carrots and radishes grow best when they’re direct sown, but many other crops can be transplanted. This allows for reliable plant spacing, helps you get a jump on the growing season in the spring, and allows for more reliable seed germination.

However, as I’ll cover below, gardeners often make transplanting mistakes. Learning about these issues can help you avoid them!

Planting at the Wrong Time

All crops have an ideal growing season. Some plants, like tomatoes and sunflowers, are warm-weather crops that don’t tolerate frosts and become stressed when temperatures drop below 50°F (10°C). Others, like peas and violas, grow best during cooler weather.

Knowing the ideal growing conditions of each crop you’re planting is key to getting them in the ground at the proper time. Many seed packets contain information about when to start seeds indoors and transplant the seedlings into the garden.

When you’re determining the best transplanting time, use environmental factors rather than dates as your guide. Since temperatures vary between growing zones, it’s difficult to say you can transplant your tomatoes after April. However, you can follow tips like “plant tomatoes two weeks after your last frost date.”

Tips for Fall Plantings

I find it pretty easy to remember that you shouldn’t plant frost-sensitive crops while the danger of frost still persists. Similarly, it makes sense that you shouldn’t transplant heat-sensitive kale or cabbage just as the first 90-degree day (32°C) arrives in early summer.

However, timing plantings of fall crops like kale, cabbage, and cauliflower can be a little tricky. These plants don’t like hot temperatures, but they also require multiple months to mature. If you want them to size up before the day length drops significantly in November, it means you often have to get them in the ground when it’s still hot.

In many areas, transplanting fall crops in August and September is ideal. It may seem crazy to stick these cool-weather crops in the ground on a blazing hot day, but this timing is right! If you wait until late September to plant these crops, they won’t mature in the fall.

Skipping Hardening Off

Many seedlings are grown in climate-controlled locations like greenhouses or your spare bedroom. While these environments provide the optimal temperatures and light that allow the small plants to thrive, they also baby the transplants. If you take these plants from their sheltered environment and move them directly to the garden, they’ll experience lots of stress.

Hardening off your seedlings can help you avoid this common transplanting mistake. This process involves slowly exposing the potted plants to the wind, sun, and temperatures present outdoors before you plant them in your garden.

If you started seedlings indoors, move your transplants outdoors to a shady location for a few hours, then move them back inside. Gradually increase the amount of time the plants spend outdoors until they’re outside for an entire day, then move them to a sunny location. Once they spend an entire day and night outdoors, they’re ready to plant. Typically, this process takes about a week.

The hardening off process is shorter if you buy your plants from a nursery that keeps them outdoors. Just keep them in their pots and let them experience full sun and wind for a few days before planting.

Recovering From Transplant Shock

If you didn’t properly harden off your seedlings, they will likely experience stress after you place them in the ground. Some signs of transplant shock include yellowing leaves, stunted growth, and/or wilting leaves. If your plant shows some of these signs after transplanting, don’t take any drastic measures to help it recover.

The plants will recover if the temperature remains in the right range and the soil remains moderately moist. There’s no need to add high doses of fertilizer or overwater your plants to attempt to remedy them. Just let them grow through the stress, and they’ll likely recover in a week or two.

Damaging Roots During Planting

When I first started farming, I was amazed at how resilient some plants were. During mornings spent planting thousands of lettuce or kale plants, I learned you didn’t need to handle their roots with much care. As long as the plants had good soil contact and moisture, they will be okay.

However, other plants have sensitive roots that demand we handle them with care. Cucumbers, melons, parsley, and cilantro all appreciate gentle handling at transplant time. Gently place the seedlings into their hole, then carefully cover the rootball.

It’s also important to be careful when removing the seedlings from their containers. Gently squeezing the sides of their container and/or poking the bottom of the soil will help you remove the roots with minimal damage.

Planting at the Wrong Depth

Planting too deep and too shallow are both common transplanting mistakes.

If you plant the seedling deeply, you risk covering the plant’s growth point where it sends out new foliage. When this happens, the plant won’t be able to grow. Planting too deep also puts the foliage in contact with wet soil, increasing the risk of rot. However, planting too shallow may lead to plants that fall over or dry out. 

So, what’s the best planting depth? You should transplant most seedlings so that the top of the root ball is even with the soil line. However, you can plant crops that develop adventitious roots deeper, since they will develop roots along the underground portions of their stems. I like to plant tomatoes, basil, and peppers, so just six to ten inches of the plant remains above ground.

Starting With Poor Soil

No matter how healthy your transplants are, they won’t thrive if you place them into a poor home. Soil that’s compacted, poorly draining, or lacking nutrients can stress your plants and make it difficult for them to establish roots.

Before transplanting, prepare your garden bed as necessary. Here are a few steps you can take to provide your seedlings with a welcoming home.

You should also avoid planting when the soil is soggy. Working in wet soil can lead to compaction issues down the road.

If you’re planting into pots or raised beds, make sure the containers are filled with a high-quality potting mix. The mix should feel loose and well-draining, but be able to hold onto moisture for at least a day.

Underwatering After Transplanting

One of the most common transplanting mistakes gardeners make is not watering their seedlings well enough. These plants are tiny, so their roots can’t reach water far away. Plus, they’re dealing with the stress of transplanting.

Watering deeply and regularly is key. After you transplant, water the seedlings well. The moisture should reach the entire root ball as well as the soil underneath. Not only will this provide the plants with the water they need, but it will also help them settle into their new home.

Check on your plants daily for the next week. If the weather is warm and dry, you may need to water them every day. However, only water when the soil is dry, so you don’t overwater. Your goal should be moist, but not soggy, soil.

Avoid overhead sprinklers and watering cans, since these can increase the chances of fungal diseases and leaf scorch. Instead, water the plants near the base in the morning or evening.

Crowding Plants

It’s tempting to pack seedlings into a raised bed or planter as you hope to harvest as much as possible. However, cramming plants together will cause the plants to become crowded and stressed as they grow—the seedlings won’t remain small forever!