You can transplant your seedlings as soon as they have developed their “real” leaves, which will appear after the “seed” leaves. Transplant when the weather is cool, and give your seedling about a week to “harden up” so it can adapt to its new climate.
When can seedlings be transplanted from a seed tray?
Mastering all of the factors in seedling transplanting can be difficult, but it is critical to the potential growth of your seedlings.
Getting this delicate transformation phase right will set your seedlings up for growth and development in the future, saving you time, money, and frustration!
Choosing the Appropriate Time
How to Identify The Leaves
Keep an eye on the leaves that your seedlings are cultivating as they are emerging from their tray.
There are two types of them:
- True Grass
- Seed Leaves (or cotyledons)
Knowing how to distinguish between these two types of leaves is important for determining when your seedling is mature enough to be transferred.
Seedling Leaves:
- On certain trees, it might not even be noticeable!
- Green peas, beans, and mangos, for example.
- If they are clear, they will be plain and flat, unlike the leaves of an adult plant.
- It is possible to see them as a pair or separately.
- They are normally found at the stem’s base.
- Like the plant equivalent of an egg yolk, it stores nutrients for the seedling.
True Grass:
- After the seed leaves, it will emerge.
- They resemble miniature copies of the adult plant’s branches, with distinctive shapes, ridges, and hairs.
- The leaves that grow after the first group of true leaves are equal to it/them and to one another.
- Carry out photosynthesis for the potato.
True leaves indicate that your plant is nearly ready for transplant and that it is time to start hardening up!
Hardening up
Hardening off is a 7-10 day period in which you steadily increase the sensitivity of your plant to outside conditions.
The process of hardening off allows your seedling to adapt to its new world and prepare for life after transplant.
Transplanting without first hardening off will shock your seedling’s system, putting it at risk.
On the first day, leave it outdoors for 2-3 hours in a shady location with minimal wind exposure.
The next day, leave it out for 3-4 hours in much brighter sunshine, and so on.
Make sure your seedling remains outdoors overnight for the last few days to acclimate to the colder twilight temperatures.
If the weather is poor on one of your hardening off days, such as a rainstorm or cold snap, postpone hardening off until the weather improves.
Weather Patterns
When the big day comes and you’re actually able to transplant your seedling to its new home, try to choose a day of reasonably warm temperatures.
Your seedling will be confused right after the transplant, and everything you can do to ease the process will improve its chances of success.
Here are a few pointers to help you keep it simple:
- Check your local vegetable planting calendar for the best transplant dates for your particular plant.
- Plant your seedlings in their trays 6-8 weeks before this date to give them plenty of time to mature.
- Transplant in the early morning, late afternoon, or on a gloomy day to reduce the amount of direct sunlight the seedling receives directly after the transfer.
- Do not, in all circumstances, transplant your seedling into a freeze! It would almost certainly perish.
NOTE: Certain plant species should NOT be begun indoors in seed trays, but should instead be planted directly outdoors in your garden or greenhouse.
Plants that are well suited to direct seeding are usually hardier and expand faster than those that perform well in a seed tray.
If all goes according to schedule, you should have big, stable, hardened-off seedlings with well-developed true leaves right around the recommended transplant date.
However, as you might be aware, gardening trips seldom go exactly as expected.
So, here are a few more wise choices you should make to give your seedlings the highest possible chance of survival.
What kind of soil do I use for transplanting?
The Seed Tray
If you’ve been keeping track, you’ll recall that seedlings get their nutrients from their seed leaves.
As a result, you don’t need a nutrient-rich potting soil to launch them in your seed tray.
Instead, choose something light and well aerated, so your seedling’s roots have plenty of space to spread and flourish.
You’ll want to make sure the soil you use is sterilized, which means it’s been prepared to be as free of contaminants as possible.
Preventing Disease
Sterilized soil is essential since even a small amount of mold or fungi may cause significant damage to a tender young seedling.
Holding your plant disease-free during its infancy should be a top priority, and your soil should represent that.
You will also get a soil-less starting mix, which is usually made from stuff like peat moss, sand, or bark, and this allows you to be absolutely certain that your “soil” is as pure as it can be.
However, keep in mind that when you remove your seedlings from the tray, you will need to replace them with the real thing.
During Transplantation
Light, well-aerated potting soil is also ideal for transplanting your seedlings.
Soils specialized for this use are easy to find online or at the nearest garden supplies shop.
Again, making the transformation process as gentle as possible would give the seedlings the greatest chance of growth.
Water the soil after it has been cultivated until it is moist but not saturated.
Using fertilizer in the planting area can be beneficial, but only at half intensity so that the seedling is not overburdened.
Safely transport your seedlings
How to Do It: Technique
The physical act of removing your seedling from the seed tray is fraught with risk.
The most important thing to remember is that you can not pull the seedlings by the stems! This is a great way to sever or hurt the stems.
Instead, flip the seedlings upside down and softly tap the bottom to extract the whole thing at once.
Make any effort to keep the soil and roots healthy. If the dirt is clinging to the interior of the pot, a quarter should be used to help ease it out.
Are the seedling’s roots curled spaghetti-style around the soil?
Then gently unwind them so that both of the roots are faced outward. When the roots are transplanted, they can grow more quickly.
Size of the Hole
The planting hole you dig should be small enough to allow the seed leaves to be seen above ground (if present).
The method is much simpler if you’ve been using a biodegradable container, such as a peat pot.
Simply dig a suitable sized hole in your bed and thoroughly immerse your pot in dirt.
Leave no portion of the pot above ground, since this will easily cause the plant to dry out.
Seedling Pruning is the process of thinning out seedlings.
What exactly is it, and why do I do it?
Thinning seedlings is the process of separating individual seedlings from a seed tray or planting bed/pot.
Thinning seedlings is best achieved before the seedlings get too close together and cramped, preventing all of them from growing properly.
It can be counter-intuitive (and a little depressing) to sacrifice one of the seedlings you’ve worked so hard to collect.
However, the competition caused by overcrowding will easily stunt the growth of your whole crop.
Where Can Seedlings Be Thinned?
It takes some consideration to determine if, when, and how often to thin out your seedlings.
When they’re still in their seed trays, it’s simple: limit them to one seedling per cell.
For seedlings planted directly into the greenhouse, your seed packet should have directions outlining the space specifications for your seedlings.
Thinning Method
Use a pair of micro-tipped pruning snips, or even a small pair of scissors, that have been thoroughly sterilized with rubbing alcohol.
Cut the seedlings at the stem’s base, but leave the roots alone or you risk destroying the roots of surrounding plants.
Look for and thin out the seedlings that seem to be the weakest, leaving the larger ones behind.
Thin them at random if you’re not sure which seedlings are the healthiest.
Thin the seedlings as soon as possible to give the survivors as much unrestricted growth as possible.
