Establishing and Transplanting Young Plants

Establishing and Transplanting


Having successfully propagated your seeds or cuttings the temptation is to put them into the next size rockwool block and straight into your hydroponic system or pot up into your final coco or soil pots. However, transplanting your stock plants too early can lead to problems with poor, slow vegetative growth. Often the root system isn’t developed enough for this stage and the plant isn’t growing aggressively enough. Some of the stronger plants will often pull through and grow happily whilst the ones with smaller root systems or plants that aren’t as advanced as the others may struggle. Now you have plants at different heights and stages of growth, not ideal for establishing a nice even canopy that is required to get the best yield from your plants.  

Establishing plants well is key to fast, even growth of your stock plants, we will look at establishment methods for plants grown in both rockwool transplant blocks and plants to be grown in coco or soil pots.


Establishing plants in coco/soil

The most common way to establish a plant for growing in coco or soil is to pot-up the cutting/seedling from a rooting block/jiffy7 into a very small pot, 10cm-13cm for example, the small pot allows the root system to develop fully through a smaller amount of media before going into a larger pot for vegetative growth and ideally into another even larger final pot for the flowering and fruiting stage. The size of the final pot and the vegetative stage pot depends on the size of the plants being grown and the number of plants per square meter or 1.2m2.


What size pots do I need to use?

            As a general rule for your final pots we recommend 30-60 litres of substrate (soil or coco) per 1-1.2m2. Therefore if you’re growing one large plant that you hope to fill this area then for your final pot size use a 30-60 litre pot, if you’re putting 2 plants in the area then use 15-30l pots, 4 plants then 7.5-15l pots etc. One exception to this rule is organic growing when using a ‘super soil’ or ‘living soil’ where much more media is required as this is the main source of nutrition for your plants.

So bearing in mind your ideal final pot size, your vegetative stage pot should be roughly half this size, this gives you 3 pot stages from rooted cutting/seedling up to final pot size. Going through these pot sizes will establish a better, stronger root system and actually encourage faster vegetative growth and more even growth across your entire crop.

It’s worth mentioning fabric pots here as they can actually allow you to miss out the middle pot size, if not going into huge final pots, as the root system that is developed within them is much better than with traditional plastic pots. Fabric pots such as the Root Mass Pots actually trap the roots that hit the side of the pot and stop them ‘circling’ round the pot as happens usually with plastic pots, this encourages the roots to branch off multiple times along its length which creates a much denser root network between the plant stem and the edge of the pot, this is often referred to as air-pruning and makes much better use of all of the soil/coco within the pot. When using these pots you can usually get away with only going into one other pot size before your final pot in fact the 1l and 2l Root Mass Pots are purposely made of such a thin grade of fabric you can simply pot the whole pot into your final pot and the roots will rip through the small pot into the surrounding coco/soil.


Potting up and watering in coco/soil pots

To pot-up plants into their first or later stage pots the technique is the same just on a larger scale. First get everything you require together then fill the pot to be used with well broken up soil/coco to the height that the transplant needs to be positioned. The easiest way to judge this it to put coco/soil in and place the small plants in pots on top to see if they sit at the desired height, add or remove more coco/soil as required.

If plants are in small pots already remove the pot and place transplant into the pot and fill around block or root ball with your chosen substrate gently firming down around the plants being careful to not damage any roots. Then to encourage fast rooting and less transplant shock, water in with a mixture of Ecothrive Biosys and a root stimulant such as Roots Excelurator for cutting/ seedlings or with the addition of a mild feed such as Vitalink Plantstart or a mild dose of your regular vegetative feed for larger seedlings/transplants or vegetative plants. The Biosys and the root stimulant help to reduce any stress and encourage fast rooting into the new substrate. Once potted up keep you plants in a nice gentle environment, high humidity not too hot but warm enough and not under too intense lighting to begin with.



Potting up and establishing plants in rockwool

Establishing plants grown in rockwool to go into a hydroponic system or to be grown on in coco is similar to establishing plants in coco/soil just with a different substrate.

What is rockwool? – Rockwool is a growing substrate usually in block or slab form but also available in loose-fill media form such as the Grodan Cell-Max Cubes, it’s made from molten rock that is spun a bit like candy floss and formed into the required shapes, it’s the same stuff often used as loft insulation but in a denser form. Rockwool holds the perfect air to water ratio and is a great substrate for hydroponic growing providing the ultimate control for experienced growers.

Most commonly used for propagation and then in larger blocks for establishment before going into a hydroponic system such as NFT (Nutrient Film technique), DWC (Deep Water Culture) and also rock wool based drip systems such as Rockwool slab drip systems or loose-fill rockwool (Grodan Cellmax) in pots. However a lot of coco growers also like to establish plants in rockwool transplant blocks such as the Grodan Delta Blocks before potting into their coco pots as its easy and mess/hassle free.

You can use rockwool transplant blocks as the next stage for cuttings or seedlings hat have been started in the Rockwool Cutting Blocks or indeed Root Riot starter blocks or Jiffy 7 peat plugs or even if started in an Aeroponic Propagator.

How do I prepare rockwool transplant blocks?

Rockwool is a completely dry and inert media, meaning it has no nutrient content whatsoever. As such rockwool needs to be soaked in a low strength hydro nutrient mixture with a root stim such as Roots Excelurator or Vitalink Root Stim and preferably also Ecothrive biosys.

We recommend using a good quality hydro nutrient such as Vitalink Max, Canna Hydro or Mills Basis at an EC value of 0.8-1.0 also use a root stimulant at full strength and finally add Ecothrive Biosys at 1g/l, add all of the above and then set the pH to around 5.5-5.8 before soaking your rockwool blocks. Soak for at least an hour or two, next remove the rockwool blocks and let them drain off until run off stops then give them a very gentle squeeze to get just a little more out before transplanting rooted cuttings or seedlings into them.

Top Tip! - Don’t squeeze too hard as you will damage the block and squeeze too much air out too, some growers prefer to hold the block in one hand and give it a gentle flick above a sink or bucket to get the excess out without squeezing.

Now an important bit! – When finished instead of placing rock wool blocks on a solid surface/tray place them on a mesh/grid such as the mesh shelves in the Garden HighPro Propagator Tent or any similar surface and water as needed.

This allows air to get to the bottom of the blocks, roots will poke out the block underneath and instead of growing under the block and wrapping up within themselves they stop when they come into contact with air, similar to the fabric pots this air-prunes your root system encouraging a larger root system to establish inside the rockwool block. Eventually you will end up with loads of root-tips just poking out the bottom of the block and when you transplant to a hydro system or coco media the plants explode with roots from the blocks and establish quickly and strongly and most importantly at an even rate.


What’s the ideal environment for establishing young plants?

Your rooted cuttings/seedlings have been taken out of your propagator with high humidity and a nice temperature and have been transplanted into your coco/soil pots or rockwool transplant blocks for establishment before going into your vegetative pots or hydro system. This change can be a big shock for your young transplants if you don’t ensure the environment is right for them. The environment within a propagator is very humid so for best establishment you want a humidity of 65-70% which is hard to achieve with warm lights and extraction/air movement without using a humidifier, for small to medium size establishment/veg rooms the Ram 5l Ultrasonic Humidifer or its larger brother the Ram 13l Ultrasonic Humidifer are ideal, for larger rooms the Mist Makers or the Faran HR-15 Humidifers are more suitable.

Temperature is very important at this crucial stage also and you should aim to keep 25-27 degrees Celsius when the lights are on and if you have a dark period a drop of no more than 5 degrees is ideal.  Ensuring your heater/radiator kicks in at the appropriate temperature is easy when coupled with the Lighthouse Wireless Thermostat. For best results use this thermostat with either the Prem-i-air 2kw fan heater or the larger Lighthouse 3kw Fan Heater but it can also be used with any of our heaters or oil filled radiators.


More top tips for establishing healthy plants:

  • Foliar sprays are excellent at helping out plants that have just been transplanted, they provide essential nutrients directly into the leaves, some also coat the leaves limiting transpiration (water loss through the leaves). This can really help plants that have been taken out of a propagator or other high humidity environment. Such products include the awesome Plant Magic Evolution foliar spray and SB Plant Invigorator which also acts as a pest killer through a physical action.
  • Silicon is great throughout the vegetative stage and first half of flower and is particularly useful for strengthening plants so they should experience less transplant shock and establish quicker, our favourite is the Grow Genius Mono-Silicic Acid which again can be applied as a foliar spray or directly into the root-zone with your normal feeding regime, This instantly bioavailable form of silicon is used straight away by your plants compared to other silicon sources that have to be broken down in the plant which can take several weeks.
  • Use a top quality light source – many growers often overlook this and will establish plants under old poorly-performing fluorescent bulbs, fluorescents are fine but they need to be in multiples to achieve enough intensity and bulbs need changing yearly. Ideally using a light with a top quality light spectrum such as the Maxibright 315w CDM Lights or even better a good quality, low wattage LED such as the Lumatek Attis 200W LED or the Maxibright Daylight 300w LED. This may seem like a wasteful expense for establishing and ‘vegging’ your plants but every stage of growth affects your end result so invest in each stage and reap the ultimate rewards.
  • Use Ecothrive Biosys weekly throughout the entire vegetative cycle to grow a massive root system and help with stress relief.

Hopefully this article will help you get through the transplanting and establishment stage without any problems and you will reap the rewards of establishing plants well in a stress-free way. If you haven’t already check out our blog post on Perfect Propagation and Maintaining a Perfect Grow Room Environment for more tips to help you achieve your plants full potential.

Take care, stay safe and keep on growing.