Root Stimulators

Root stimulators are used in the first few weeks of a plant's life, when the root mass is the limiting factor on everything else. Get the roots established quickly and the veg and flower stages take care of themselves; get it wrong and no amount of bloom booster later will fix it.

When they earn their money

• Cuttings and clones – the window between taking a cutting and it rooting is the riskiest fortnight of the whole grow. See propagation nutrients and cloning products.
• Transplants – moving from propagation media into a bigger pot checks growth for several days. A root stimulant shortens that.
• Early veg – the first two to three weeks in the final pot, while roots are colonising the medium.
• Recovery – after root damage, overwatering or a pythium scare.

What is actually in them

Most root products are one of three things, and it is worth knowing which you are buying:

• Hormonal – auxins that directly trigger root initiation. Fast acting, used at propagation.
• Vitamin and amino based – B vitamins and amino acids that reduce transplant stress. Canna Rhizotonic is the best known.
• Biological – mycorrhizae and trichoderma that colonise the root zone and extend its reach. These are slower but persist for the whole grow. See beneficials and inoculants.

Hormonal and biological products do different jobs and can be used together. Two hormonal products at once is money wasted.

Getting the root zone right first

A stimulant will not rescue a root zone that is too wet, too cold or too dense. Roots need oxygen as much as they need water, which is why coco and perlite outperform heavy soil for fast establishment, and why root temperature around 20°C matters more than most people think. Fix the environment, then add the stimulant.

What we stock

Root products from Canna, Athena, Buddhas Tree, Plant Magic, Mills, House & Garden, Dutch Pro and Ecothrive. Pair with a base nutrient, and for the other end of the cycle see flowering boosters.

Root stimulator FAQs

How long should I use one?
Through propagation and the first two to three weeks of veg. After that the roots are established and you are feeding for growth, not initiation.

Can I use one in flower?
Biological inoculants, yes – they keep working all cycle. Hormonal root stimulants, no real benefit.

Do I need one if I am using a good base feed?
For seeds in soil, not really. For cuttings and transplants, it makes a visible difference.

Why buy root stimulators from The Hydro Bros?

We are a hydroponics shop in Croydon and we take cuttings every week, so we know which of these actually shorten the rooting window. Discreet UK and European delivery, and excellent customer reviews on Trustpilot.