How you can safely transplant seedlings

Have you ever wondered how to transplant seedlings? Planting and transplanting seeds is an annual ritual. Depending on what you're looking to grow, a learning curve may be required. There are plants that transplant well and others that go into transplant shock. And there are times to remember too.

The type of starter you use will also affect how you transplant seedlings. The depth of planting is also important. Perhaps you've used starter pots in the past and haven't had success, or maybe you want to try a new method of sowing to prepare for the hardening off. There are solutions to these problems!

The fact is, with a good job in the starting process, you will be on the right track when the growing season comes. Your goal of growing delicious vegetables that will provide you with good nutrition can easily be achieved if you prepare appropriately and follow the correct procedures.

So let's discuss a few specifics about transplanting seedlings!

When should seedlings be transplanted?

Knowing how to transplant seedlings will help you get started in spring. Source: IRRI Pictures

Your USDA zone and frost dates are the key indicators of when to start new grafts. You don't want to transplant seedlings before the first frost when they are sensitive to the cold, and you don't want to plant plants in the cool season when the weather is getting warmer. Another factor to consider is whether you want to place them outdoors or inside in a container. Let's cover a few tips to help you determine if the time is right.


This only applies to plants that live in your yard or outdoor grow space. You don't need to harden plants that you plan to keep indoors. After you've started the seeds indoors and taken care of each seedling, follow the curing process of individual plants before transplanting them. New seedlings are certainly not suitable for the outside temperatures immediately after germination, so gradually expose them to the elements.

To harden them off, take your plant seedlings outside for a few hours first during the warmest part of the day. Then bring them in. Over the next few days to two weeks, increase the amount of time they spend outdoors. First, keep them out of direct sunlight and then gradually expose them to direct sunlight so that they are not scalded by the direct sunlight. Finally, your plants can stay outside overnight and are ready for full sun after transplanting.

You can also harden seedlings in a cold frame. These are great for those who need to cure in the spring. Use the same steps as curing without a cold frame, but then leave the frame in your yard. Just close the lid of the frame if the temperature is too cold; A good cold frame ensures that the sunlight reaches the plant well. Make sure to open the cold frame on warmer days to allow excess heat to escape. The cold frame is a great way to protect tender seedlings from drying winds or unexpected frosts.

Cool timing of the seasons

Plants in the cool season can withstand the cold but do not do well in hotter temperatures. For this reason, in early spring, transplant outdoors 2 to 3 weeks after the last frost date. This applies to most of the USDA zones with different seasons or cold winters. In more tropical areas or those that have more warmth than cold all year round, start plant growth in late fall to plant in winter. Some cold season plants that need to be planted in late spring can also be planted 2 to 3 weeks before the first frost date. The key is that there is enough time between the transplant time and any severe freezing conditions for the plant to establish itself.

Time of the warm season

Warm season crops are always planted after the last frost date in spring. They tend to live and only produce during warm weather. Many annual plants are warm year crops. Here it is important to aim for a transplanting time of 2 to 3 weeks after the last spring frost. Gardeners in more tropical areas are better suited to only growing outdoors during the warmer months and can only leave the cold season harvest to the cooler winter months. Those with pronounced, long winters need to act quickly and decisively. Michigan, for example, has a lovely temperate summer when heat-loving plants thrive. The only catch is the arctic winter that's just around the corner. In very hot areas, the plants do not do as well in extreme heat and often finish their cycle in late summer.

In some cooler areas of the country, sowing in winter means that your plants will be ready for use and have already acclimatized to their climate by the time the ideal time for replanting comes. This technique is really useful for people who want to maximize their limited warm weather season.

Transplant shock

Transplant shock occurs when the roots of seedlings are disturbed during the transplant process, resulting in stress for the seedling. Do not start these plants indoors. Instead, sow them right in the garden. Make sure they are not in danger. Sometimes a towel of frost or shade will be helpful at the beginning of the growing cycle. It's also a good idea to cover them up or create a barrier to keep animals or pests from eating them!

Some examples of species that are difficult to replant are root crops like carrots or parsnips. Since the main taproot of the plant must go straight down, putting it in a starter block or cell can cause the root to twist unnecessarily. Other species only have fragile root systems that can be easily crushed when transplanting. Check in your seed package whether your variety should be sown directly or started with another method.

Starting methods

Seedlings in compostable cellsCompostable starter cells can be planted with the seedling. Source: missellyrh

There are many ways in which you want to start plants that are not sown directly into the garden soil. Find out which of these is best for you and you will be more successful when it is time for a transplant.

Earth blocks

Seed pots are not required for soil blocks, which can lead to disturbed roots when planting seedlings in garden beds. In a starting block, potting soil is combined with elements like compost that allow a shape to hold without a container. The potting soil is combined with water to form a self-contained block that retains its own shape either by pressing into a soil blocker or by being shaped into a ball. The seedling that grows out of the earth block can be planted directly in the garden with a hand trowel if the weather is right.

Sow starting cells

Don't have a floor blocker? Consider using our epic 6-cell seed starting trays. These cells are an excellent way to grow your seeds in a container filled with a culture medium of your choice. They have a hole at the bottom that you can slide the new grafts through instead of breaking a thin plastic cell tray to get them out. Even seedlings that would otherwise have a disturbed root ball for transplanting suffer significantly less agitation with these cells. They have air cut slots on each side that encourage healthier root growth for your seedlings. Start your plants in these cell pots, then move them to the garden or larger containers as they grow.

Plastic pots and trays

If you've been gardening for a while, you are likely familiar with flimsy single pots and plastic planters. Often these are combined with a heating mat and a grow light to make it easier to get started. Fill them with a starter mixture, put in seeds and water, and wait for your seedling to grow. For transplanting, remove the seedling after it has developed its real leaves and has hardened and place it in a hole in the ground or in a pot. These work well for a seedling that will not take shock from transplanting. However, they tend to deteriorate over time. Taking them out of the pot for planting will occasionally leave some soil that you need to tap out of the container. Instead of using these on shock-prone plants, save them for those that are hardy in the roots department. These are often one-way starters.

Peat pots or other decomposing containers

Another way to avoid gardening at risk of transplant shock is to use peat pots or similar containers made from coconut-coconut or compacted manure. These should be planted right in the soil, pot, and everything. Before transplanting, carefully tear apart the bottom of the pot to allow better access for the roots. Peat is used in many soil mixes and will biodegrade over time, as will coconut or manure. Gardening with peat pots is a preferred way of working with a seedling for many. Another benefit of gardening with peat pots is that they will retain water and keep your seedlings moist throughout the startup cycle.

Pelleted starters

Some can find kits that contain pellets that expand when warm or hot water is added. These pellets become a self-contained starter cell, generally made of something like coconut contained in a fine mesh. They work very well to start sowing, but as your plants grow they will need to be upgraded to a much better medium over time. If using these, cut the mesh off with a sharp knife or scissors before planting, as the mesh won't break up as quickly as the rest of the pellet. If the roots are already through the mesh, cut lines along the sides to allow the mesh to expand outward as it grows.

Temporary transplant tips

Pellet seedlingCoconut pellet seedlings have a fine web through which the roots grow. Source: Phil and Pam

You may need to do some plumbing in your yard, and the hole you need to dig to access the plumbing is just under the roots of an established shrub or other species. In that case, move the established shrub, Tree or bush in another area. Note that the movement could potentially result in shock. So take care and be careful when moving them. Carefully dig a perimeter in the soil around your established flora for an indication of the size of the root mass. Prepare a planting hole that is at least a few inches wider than the plant's root ball.

Choose a spot with enough sun or shade and make sure you have soil suitable for the plant. Remove scattered weeds. Depending on how long it will be there, you may want to put some fertilizer in the hole. Place the root ball in the hole and replace the soil around the space between the perimeter of the hole and the stem. Make sure there are no exposed roots and that you are planting in the right weather as it is usually best to transfer plants in temperate seasons. After moving it, pour it in to fix it in place and to add soil moisture to encourage root growth.

In-soil transplants

For the seedlings that go straight to the garden, use a trowel or shovel to dig a hole large enough to fill all of the contents of the cell, starter pot, or block. If you are working with plants like tomatoes or flowers, add a little fertilizer to the appropriate hole for that particular plant. If necessary, remove the starter pot by turning the pot upside down. Put it under the surface of the soil and move the soil around the stem safely. Make sure the root tips are covered and add water to keep the soil around them moist. Another way to keep the soil moist is to cover the surface with some mulch. Check newly placed seedlings every few days to make sure they are doing well in your garden.

If you are using a coconut pot, peat pot, or dung pot, these starts can be planted in their pot. Be sure to break up the bottom of the pot so that the young roots have free access to the soil under the pot. Over time, the rest of the pot will crumble into the soil, but you want to make sure the root system has no obstacles to growth.

Transplant depth

One important thing to consider when gardening with grafts is the depth of a seedling. This is very different for different plants. For example, trees should not be planted at the same depth as peppers. They have different root systems and different planting depths. Trees should be planted at the same depth as they are in their starter pot, being careful not to cover any finishing joints. In contrast, if desired, bell pepper seedlings can be buried with their stems down to the lowest set of leaves, as they form additional roots along their stems like tomatoes. Before you begin, do a little research to learn how to transplant your particular seedling.

Container transplants

Transplanted seedlingsMonitor newly transplanted seedlings for transplant shock. Source: Kirsty S

If you live anywhere with a short spring and summer, consider growing some of your plants in the garden for part of the season and then moving them indoors. In this case, containers are essential. Plants like tomatoes do well in the heat, but autumn or late autumn does not have an easy time for a tomato plant. Consider planting them in a container where they can be in the garden for part of the season and indoors for the rest. The same process outlined in the previous section applies to a container garden. Prepare the hole large enough for the seedling. Then plant it.

Note that the depth you replant applies to containers as well as ground plantings. Don't go too deep or too shallow! If you're dealing with a perennial that has been floating around for a while, it may be easier to increase the size of its planter over time rather than having a tiny seedling in a giant planter. This also reduces the risk of overhydration; less soil means less wet conditions for a young seedling.

frequently asked Questions

Q: How big should seedlings be before transplanting?

A: It depends on the plant. One way to tell when seedlings are ready for the garden is to look for at least a few fully developed real leaves.

Q: How do you transplant small seedlings?

A: Seedlings are tender and should be handled with care. In order not to disturb the roots, use peat starters, starter cells with large holes in the ground, or earth blocks. Containers that decompose also prevent root disorders.

Q: How long can seedlings stay in trays?

A: It depends on the vegetable or fruit you are growing. Most of them are ready to move into after a few weeks. Make sure the plant has at least a few real leaves, and make sure that they can withstand outside conditions or otherwise protected from inclement weather.

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