MAMMOTH® Starter Plugs provide a 50/50 mix of coco coir and sphagnum peat moss, along with excellent moisture and aeration for all media applications.


MAMMOTH Starter Plugs


Why Mammoth Starter Plugs?


How Mammoth Starter Plugs Can Replenish Your Plants


Application & Specifications

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MAMMOTH Starter Plugs


MAMMOTH Starter Plugs make it easy to plant and grow. Plant seeds or clones in the pre-drilled holes, then water or mist, keep your humidity consistent, and transfer when ready.


The 50-deep-cell tray offers 65mm of media; over 30% more than traditional trays.


Plant, Grow, and Go


Mammoth Starter Plugs are made of a 50/50 mix of coco coir and sphagnum peat moss, providing ideal conditions for seeds or clones to start. No pre-conditioning is required – just plant and grow.


All the details on usage, application, specifications, and more.


Mammoth Starter Plugs are highly compatible across all media and standard grow trays.


For best results, follow our simple recommended application rates noted below.


  • View our Material Safety Data Sheet


Directions for Use

  • Place your seeds or cuttings into the predrilled hole at the top of your Mammoth Starter Plug
    • Do not plant your seeds/cuttings too deep as to provide the most media for root development
  • For seeds, keep your trays in warm, dark place to optimize germination rate
    • Be sure to never reach temperatures of 90°F/32°C or above to prevent seed dormancy.
  • Monitor the moisure in your Mammoth Starter Plug.
    • You will want your plug to remain damp but not soaking. Your Starter Plug will not retain any more water than needed for root development.
  • Once you have visible root growth, you may transplant.

General Use / Purpose of Product

  • MAMMOTH Starter Plugs provide growing media to support beginning phases of plant growth

Product may not be registered in all states.

MAMMOTH Starter Plugs Registration Map


What are the main benefits of using Mammoth Starter Plugs?

Mammoth Starter Plugs come pre-moistened and ready to use when the packaging wrap is removed. They’re 65mm deep – deeper than the standard 50mm plug – which provides more room for early root development. Mammoth Starter Plugs use a food-grade polymer/binding agent and are very clean; they also do not turn hydrophobic if they happen to dry out and are easily rewettable. Plugs that need to be rewet will expand back to their original shape and will be in contact with the cell walls.

Are Mammoth Starter Plugs OMRI/organically listed?

No– because of the plastic trays which are made of food grade plastic. Besides the trays, the plugs media has an OMRI certification.

I already use a plug tray, how are these different?

Mammoth Starter Plugs are deep plugs, providing 65mm of media compared to traditional plugs. This extra deep media gives growers more surface area for roots to colonize. They come premoistened and are easy to rewet – they do not turn hydrophobic like some other plugs might. 

What are Mammoth Starter Plugs made from?

A near 50/50 mix of coco coir & sphagnum peat moss, with trace amounts of biochar and perlite added for porosity and aeration. Our plugs come pre-moistened.

How many plugs/cells per tray?

50 cells – deep.

What are the individual plug dimensions?

40x40mm on top; 65mm depth.  

What are the dimensions of the tray?

10”x20” – a standard dome will fit. 

Will a standard dome fit on the tray?


What is the storage/shelf life?

There is no limit as long as trays are sealed. 

How do I store Mammoth Starter Plugs?

Keep sealed until ready to use. Always store out of direct sunlight and in a cool area. 

Can Mammoth Starter Plugs be re-wet?

Yes, easily. They can be rewet from the top down, let them soak for 10-15 minutes then dump any extra moisture from the bottom tray.

Can Mammoth Starter Plugs be mechanically transplanted?

Yes, they’re compatible with a mechanical transplanter.

Is it OK to see any mold growth on Mammoth Starter Plugs?

Yes, it’s OK. From time to time you may notice a little bit of mold on them, which is normal and to be expected. It’s a Penicillium mold which is harmless and goes away with light, water, or a few sprays of CannControl. 

Can I use Mammoth Starter Plugs for my seedlings and cuttings?

Yes, Mammoth Starter Plugs work excellent for plant cuttings. They work OK for some seeds, but it depends of the type of plant seed being planted. 

Can I use Mammoth Starter Plugs with other Mammoth products?

Yes, we highly recommend this. You can apply Mammoth Myco, Mammoth P, Mammoth Silica, and Mammoth Garden Grow Me to the plugs to encourage early and robust root development.  

CannControl can be applied to the plug tray before plants or seeds are inserted if penicillium mold is present. You can use CannControl on mature cuttings to ensure they have a clean start to their life.

Are there any products I shouldn’t use with Mammoth Starter Plugs?

No – our plugs are compatible with any nutrient/fertilizer regimen.