Transplanting, pricking out, & potting on Tips.

Transplanting tips are necessary to have when you live in a temperate, or short season zone. Being able to grow those long day season plants often means getting a head start indoors, so getting pricking out, potting on, and transplanting right is a must to keep our seedlings thriving to harvest.

But why bother?

There are various reasons for having to move our seedlings into another pot before going outside to their final position, or even for a house plant. Let’s take a look at those. The first is that each seed is a different size and only has enough nutrients in it to get those first leaves, the cotyledons, out of the protective coating and the roots established. After this the plant is reliant on the compost you’ve put it in. However, not all starter compost mixes have nutrients in them, and this is why your seedlings will quickly start to die. If they are in small, or shallow trays/pots, those with tap roots, or fast growing roots that don’t like being disturbed, such as beans and squash will quickly hit the bottom of them. They will then start to coil and become root, or pot bound.

If you have multi sown seed, not only will they quickly use any nutrients in their compost, but they will get leggy (too tall), weak, and rooted together. This will make separating them more difficult. Giving each plant the correct size pot for its stage in growth helps it to thrive.
In the case of a house plant it may not be that it needs a new container at all. It may just be that you are splitting it to propagate it, or refreshing the compost it is in.

Choosing your container.

Choosing the correct sized container for your seedlings stage of growth is also important. It’s tempting to big from the start, and just cut the work out. The problem with doing this is that it takes a lot of compost to fill that pot for such a small plant. It also takes a lot of water compared to the size of the roots your plants has. Trying to keep the balance of moisture your plant needs just became more difficult, can cause pest and disease issues. This is aside from the fact that the excess water will also be leaching the nutrients out through the compost too. It’s better to think of potting on like children needing a new coat; just enough room to grow into.

Which compost?

This is pretty much dependent on exactly which plant you are dealing with. For most vegetable and flower seedlings a general purpose potting compost should be fine. However, not all composts are created equally. In fact some leave rather a lot to be desired since many companies are cutting corners to meet demand. Screening also seems to have become an issue, and I have found that many composts still contain large enough chunks of wood chips that this will inhibit growth in small containers.

I suggest resifting composts to remove lumps, and if not already added, consider mixing in a good quality vermiculite at 15% volume to aide water and nutrient retention. Alternatively, you may want to create your own mix, which is what I do. I have a separate category discussing Vermicomposting and also Composting, as well has how I make my own basic mix with them.

Some seedlings, and house plants do very well in Cactus potting mix, but you will need to monitor these for water since it is very free draining. Depending on how long the plants are in this, or indeed any compost for house plants or containers in general then feeding on a regular basis is a must.

Method

Fill new container with compost, and make the appropriate sized hole for the seedling. If pricking out from multi-sown seedlings- you can use a dibber, pencil, plant label to gently coax out each seedling. If they are more tightly packed- gently tip them out, wash off the compost, and tease the roots apart. Hold the seedling by the first leaves, and place in the hole up to those leaves. In the case of such as Tomato plants- if these have got leggy, remove the first leaves, and plant deep up to the first true leaves. Gently firm the compost in around the seedling to prevent air pockets around the roots. Add more compost as needed. Water in, and again check the compost level.

For larger plants moving up a pot, use the pot they are in to create the hole depth. Many seedlings can be planted deeper to encourage a stronger plant, and rooting. However, most established plants won’t like this. If the plant has a crown, such as a Strawberry, or Rhubarb, these must be planted above the soil, or they will rot.

Transplanting outside

When transplanting our seedlings outside care must be taken with many. However, there are a few exceptions. Cool weather crops can often be started in module trays and then transplanted straight outside with some protection. Warm weather crops need more care for the most part. They have not been exposed to the wind, fluctuating temperatures, or direct sun. We must introduced them to it slowly to avoid damage. Take your plants outside for small amounts of time per day, and increase this slowly over the next few weeks. It’s easier with a greenhouse, or cold-frame, but not everyone has them.

Make sure that all chances of frost have passed before finally planting out. I prefer to do so in an afternoon, because this way the soil is warm, but the plants won’t have to deal with the midday sun. I add any amendments and water straight in to the hole, such as for tomatoes, before placing the plant in to it. If the weather is going to change, make sure to cover the plants for the night, and remove again in the day.

You can see my video here-