Transplant Seedlings in Hydroponics (My Best Guide)

Even though everything about the question sounds like it, it is pretty easy to transplant seedlings in hydroponics yourself!

So, when exactly should we start transplanting them?

A seedling is ready to be transferred to a hydroponic system when it is at least 3 inches (8 cm) in height and there are at least two or more true leaves, that is, the ones other than the cotyledons (in other words, seed leaves).

When To Transplant Seedlings Hydroponics
When To Transplant Seedlings Hydroponics?

Any transplant attempts before the seedling meet the above criteria, and you risk a variant of problems later, which we are trying to minimize as much as possible.

What to Do before transplanting seedlings into the hydroponic system?

Before we start the transplanting process, we must first decide on the hydroponic system we will be working on. Here we are getting a load of choices, of which most are pretty simple and need minimalistic preparation.

One of the simplest setups is the Water Culture method which is recommended for beginners.

But the essential prerequisite for almost all hydroponic systems is a pump (or, better, a submersible pump). Aside from the pump and the plants, we will be needing:

What should be done first before transplanting the seedlings into the hydroponic system
What should be done first before transplanting the seedlings into the hydroponic system
  • A support framework,
  • A reservoir for storage of water and nutrients,
  • A growing medium (which varies from one hydroponic system to another),
  • Tubes which can move water and nutrients without choking, 
  • Nutrients solution and pH control,
  • Water, 
  • And finally, light 

For light, we must decide whether we are going with sunlight or artificial lights for indoor farming. LED lights are better all-around, but you can also consider Metal halide or fluorescent bulbs.

For indoor lighting, ensure that your plants receive at least 6 hours of light for proper growth. Aside from the initial setup, we also need to provide a steady supply of clean water and nutrients for your plants throughout their growth. 

When to transplant seedlings in hydroponics?

It’s not very hard to know exactly when to transplant seedlings in hydroponics. In most cases, a seedling can easily be transferred to an hydroponic system when it crosses 3 inches (8 cm) or more in terms of heights.

It should also two or more true leaves other than the cotyledons (seed leaves). Once these two conditions are met, then you can easily start the transplant mission.

How do you transplant seedlings in hydroponics?

To kick the entire process off, you first need to plant the seeds in the soil and wait for them to germinate and grow at least 8 cm (about 3.15 in) in height and two true leaves. To safely remove the soil from the roots, we need to follow these simple steps:

How do you transplant seedlings to hydroponics
How do you transplant seedlings to hydroponics?
  • Prepare a big enough trough and fill it with clean water to wash the roots.
  • Loosen up the soil a bit and gently scoop out the seedling along with the soil with one hand underneath the mass to prevent damage to the maturing roots. Gently tap on it to remove too much dirt and proceed with the next step.
  • While still holding the bottom of the seedling’s root and soil mass, submerge it into the water and sway it to remove the dirt from the roots gently. Make sure the stem does not touch the water.
  • While holding the stem steady, use a second can of water and pour some over the roots to clean the roots further. This step helps to clean as much soil as possible so that later soil does not clog up the pump or the pipes.
  • If dirt is still latching onto the roots, do not try to remove those forcibly, as it can damage the still developing fibres.
  • Now prepare the hydroponic system for the final transfer.

From here on out, the process can be vastly different depending on the type of hydroponic system used. But most of the time, you have to spread out the seedling’s roots on a hydroponic netted pot evenly to increase the surface area of the seedling’s roots.

This ensures the seedlings are not deprived of essential nutrients and enough water. 

Now add a soilless hydroponic medium around the seedling’s stem to support it upright. This will ensure the seedlings grow straight and receive maximum light when they develop more leaves.

This also guarantees enough space for other seedlings by not infringing upon their headroom and blocking light which might stunt growth. This should also allow a high-density hydroponic system with high yields. 

This is the general practice for most hydroponic systems, but there are many practices for other hydroponic chambers. But in all of them, we must ensure all the seedlings are well hydrated and nutrients are properly absorbed. Fertilizers may be added but in a controlled manner.

Frequently Asked Questions (FAQs)

When can I transplant Rockwool seedlings?

The fact that there is no chance of harming roots while transferring seedlings to the hydroponic chamber is one of the Rockwool method’s biggest benefits.Generally, the Rockwool method is quite a mess-free way of getting seedlings which are also relatively fast, taking no more than 7 to 10 days to be ready for transplanting.

When can I transplant a solo cup?

If you have planted the seedling in a solo cup, you should try to transfer it to a bigger pot or hydroponic chamber once you see several roots, especially from its tap roots. That is a usual indicator you need a bigger space for your seedling. You should wait out 1 to 2 weeks normally before transplanting it. Although waiting too long can be harmful as it stunts the growth of the seedling horribly.

How long should a seedling stay in a solo cup?

Though the answer varies on the condition provided to the seedling, it is usually a good practice to observe it for a cluster of roots forming, especially around the tap root. Generally, the time for it to reach the stage mentioned above is within 1 to 2 weeks, but the primary indicator should be root formation.

However, a word of caution: don’t leave the seedling in the tiny cup since this will restrict its growth, even at later stages. Instead, take the proper care of it.

Does sugar water help transplant shock?

One of the most contentious issues in horticulture, although the solution is still not entirely evident. But the most learned answer on this topic will be that a little sugar solution at the roots of the transplanted seedling helps with transplant shock.

The reason is that it stimulates microbial growth (the ones essential to the plant for nitrogen fixation) at the root nodes. So little sugar can help the plant, but if done in excess, it can cause reverse osmosis, which essentially starves the plant by pulling water out of the plant to the soil.

Should I give nutrients after the transplant?

As hydroponic plants do not have soil to absorb nutrients from, adding small proportions of nutrients (about one-fourth of the usual) in the misting water to the seedlings is advised. It is given in small quantities because excess use of nutrients at this stage will make the transplant shock worse and damage the young and tender roots from the sudden and drastic increase in nutrients. 

Should I fertilize seedlings after transplanting?

It is usually ill-advised to use the regular amount of fertilizers for the seedlings after an immediate transplant. This is because the young seedlings can go through a transplant shock or damage their roots permanently due to the sudden uptick of nutrients in the unfamiliar environment,

which is vastly different from the state it was in previously. So, fertilizers should be used in a small quantity (only as much to provide enough nutrients to repair the damage done during transplantation) than it usually takes.


With the improvement in techniques in hydroponics over the last few years, it is easier than ever to get on with it. Even dedicated kits help you start hydroponics and grow your farm. You get to decide the scale and throughput of your farm and customize it to your suiting.

Transplantation might be challenging, but it is getting easier with the passing year due to better species of plants in use. It is a wonderful time to start your hydroponics plant without the usual headache that comes with traditional gardening.

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top