Activ8EXTRA High Nitrogen Liquid Lawn & Garden Fertiliser, 16-2-5 - 4L

Activ8EXTRA High Nitrogen Liquid Lawn & Garden Fertiliser, 16-2-5 - 4L

Fortnightly boost for leafy greens, trees and turf

High-nitrogen liquid fertiliser and soil conditioner enriched with seaweed, fish, blood and bone, plus humic and fulvic acids. It promotes lush green growth, improves soil health, feeds beneficial microbes and enhances nutrient availability.
16-2-5 NPK + T/E & Seaweed Fast Green-Up & Growth Fixes Yellow, Weak Lawns
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$62.95
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Description

Boosted Liquid Fertiliser for Lawns, Plants & Soil Health

High-Performance Liquid Fertiliser to Feed Your Lawn and Revive Your Soil

Activ8EXTRA is more than just a fertiliser, it’s a biologically boosted blend designed to feed both your plants and your soil. Infused with organic ingredients like seaweed, fish and fulvic acid, it delivers fast-acting nitrogen along with the natural compounds your soil microbes crave. Whether you’re growing a lush lawn, thriving veggie patch, or leafy trees, Activ8EXTRA helps you build healthier soil and deliver greener, stronger growth, all in one easy liquid application.

Use Activ8EXTRA when your lawn or soil needs a nitrogen boost, improved biology, better water absorption, recovery after chemical use, or preparation for planting as part of an organic or regenerative program.

I started using this about a week ago after adding Nature's Soil wetter to my lawn. Wow..... What a difference it makes. My grass in responding so quickly. Before it was hard to get it to do anything. This stuff is like gold in a bottle. I had some dead and dying areas of grass but now they are lush, green and filling in again.
— Stephen

Why Choose Activ8EXTRA:

  • Strong leaf growth with high nitrogen
  • Feeds and activates beneficial soil microbes
  • Improves soil aeration and water penetration
  • Enhances nutrient uptake and micronutrient availability
  • Reduces fertiliser leaching and locks nutrients in the root zone
  • Made with fish, kelp, humates, blood & bone, and fulvic acid
  • Works across lawns, garden beds, trees, and vegetables 

Nutrient Profile: 

N
Nitrogen
16%
P
Phosphorus
2%
K
Potassium
5%

 

Feed Your Lawn & Soil the Right Way. Activ8EXTRA gives your lawn and garden the nutrients they need and builds the soil biology to sustain long-term growth. Whether you’re a weekend gardener or managing large-scale turf, this all-in-one fertiliser helps your landscape flourish, from the soil up.

(A8X04L)

Features

Specifications

NPK:
 		 16-2-5 + micronutrients
Additional Components: Fish hydrolysate, providing amino acids and natural growth enhancers
Seaweed (Ascophyllum nodosum), rich in cytokinins, auxins, and anti-stress compounds
Humic and fulvic acids (USA-sourced), for increased nutrient chelation, improved soil CEC, and microbial stimulation
A blend of trace elements that address common deficiencies in Australian soils

How it Works

The Science Behind Activ8EXTRA:

Activ8EXTRA is formulated as a high-analysis nutrient input combined with biological stimulants to improve nutrient use efficiency (NUE), soil structure, and rhizosphere performance. By integrating fast-available nitrogen with organic carbon sources and fulvates, it supports both immediate plant uptake and enhanced nutrient mobility within the root zone.

The formulation promotes microbial activity responsible for nutrient mineralisation, helping convert unavailable nutrients into plant-accessible forms while improving overall soil biological function. This increased activity contributes to better soil aggregation, aeration, and water infiltration, reducing compaction and improving root zone conditions. In addition, fulvic compounds enhance nutrient chelation and transport, improving uptake efficiency and reducing losses through leaching. The result is more stable nutrient availability within the rhizosphere, supporting consistent vegetative growth, improved canopy development, and faster recovery from stress.

Suitable for integration into fertigation, foliar, and soil-applied programs, Activ8EXTRA is particularly effective where rapid nitrogen response is required alongside improvements in soil biology and nutrient efficiency. Performance will vary depending on soil type, organic matter levels, and environmental conditions

Application

 

Type Application Rate  
Apply fortnightly or when feeding is required

 
General application:

75-100ml/100sqm 

7.5-10L per Ha
Watering Can:

20-30ml/9L

*Spread evenly across the area to fertilise.
Hose‐on Bottle (Seasol/weed ‘n feed etc.) or Hortex Sprayer

Mix the minimum amount of water with the product/s to allow you to cover the required area/s.

For example, for my front yard, using an old weed n feed hose‐on bottle, I add 100ml of each Seaweed Secrets, Activ8mate or Activ8EXTRA, and Nature's Soil Wetter, then top up with enough water to allow you to evenly cover it using the hose‐on bottle (I add about 600ml water), then evenly hose‐on.
Pressure/Knapsack Sprayer You need about 10 litres (a little more or less won’t hurt) of water to be applied per 100m², so take that into consideration when applying. If you have a smaller sprayer, either do several smaller applications (i.e., covering 50m² at a time and repeat until the entire area is covered), or over a larger area spray with the required amount. Give a light water‐in. If using a Hortex sprayer on setting 2 without the restrictor, you shouldn’t need to add water, but if you do, just add as little amount to cover the required area.

 

  • For best results, apply fortnightly during the warmer months.
  • During cooler months, apply less often and/or at lower strength.
  • Best applied all-year round to continue improving soil and feeding microbes.
  • Agitate well before use.
  • As there are many conditions that affect the exact amount needed and the frequency of application for each product, there is no one-size-fits-all solution.

 

Safety

Safety Guidelines

Keep out of reach of children. May be harmful if swallowed. If eaten seek medical help. ALWAYS TRIAL BEFORE CHANGE. Before a new rate, product or application method is used, a small trial is recommended. Warranty of this material, either expressed or implied, is limited to a guarantee of the composition as shown on this label in as much as uses are beyond the seller’s control. For the same reason, the seller is not liable for any injury to any living thing, crops, soils, or materials which may result from the use or storage of this material. As this is largely a mineral-based fertiliser made from natural resources, the analysis may change slightly.

NOTE: not compatible with iron-based products

FAQ

What is Activ8EXTRA used for?

Activ8EXTRA is a high-nitrogen liquid fertiliser enriched with organic ingredients like seaweed, fish, and humates. It's designed to feed lawns, leafy plants, and trees while improving soil structure and microbial health.

What’s the difference between Activ8MATE and Activ8EXTRA?

Both are biologically enhanced liquid fertilisers, but Activ8EXTRA is higher in nitrogen and better suited for vigorous growth in lawns and leafy plants. Activ8MATE has a broader nutritional profile for general soil and plant health, especially during seasonal transitions or when microbial activity needs a boost.

How often should I apply Activ8EXTRA?

Apply every 2–4 weeks during the active growing season. For best results, pair with watering or rain to move nutrients into the soil.

How much Activ8EXTRA should I use?

Apply 75–100ml per 100sqm, diluted in water. Always trial on a small section before widespread use, especially with new application rates.

Can I use Activ8EXTRA on all lawn types?

Yes, it's suitable for all Australian lawn varieties, including buffalo, couch, kikuyu, and zoysia.

Is Activ8EXTRA safe for all plants?

Yes, it can be used on lawns, leafy green plants, trees, and shrubs. Avoid use on young, sensitive and natives plants unless tested first.

Should I mow before or after applying Activ8EXTRA?

Apply before mowing for optimal absorption and to prevent product removal through clipping.

Do I need to water in Activ8EXTRA?

Yes, a light watering after application helps deliver nutrients to the root zone and activates soil biology.

Can I mix Activ8EXTRA with other products?

Yes, but avoid mixing with iron-based products as they may be incompatible. Always jar test before combining products in a tank.

Is Activ8EXTRA pet- and child-safe?

Yes, once dry. Keep children and pets off treated areas until the product has fully dried to avoid contact with active ingredients.

What are the key ingredients in Activ8EXTRA?

Activ8EXTRA contains nitrogen, phosphorus, potassium, trace elements, seaweed, fish, and high-quality humates including fulvic acid.

Can I use Activ8EXTRA during hot weather?

Yes, but apply early morning or late afternoon and avoid high-heat periods. Always water in well to prevent plant stress.

Reviews

5.0 / 5

customer reviews

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So easy

Everything in the one bottle. brings my lawn back to life.

Activ8EXTRA

Just a very nice fertiliser for all plants and lawns for a nice little boost.Thanks Plant Doctor

Fantastic

I was recommended this by a friend to supplement my application of slow-release granular fertiliser. This liquid product is much faster acting and easier to apply. Highly recommend.

Activ8 Extra

Recently decided I would do more to look after my lawn, to help me achieve what I wanted this product has not only sped up the process but I’ve now got a really healthy lawn!! Highly recommend

working a treat

in combo with a range of plantdoctor products my lawn is going great!

Activ8EXTRA

Another great product from the team at Plant Doctor. Was drawn to this company as they have a strong background in horticulture/agriculture products where it is important to provide effective and efficient use of products. Backed by science, their products are easy to use with lower application rates avoiding unnecessary overuse of products.

Fantastic for pretty much everything

I’ve used this product on pretty much everything on my garden and seems to be doing a fantastic job.

Activ8EXTRA Boosted liquid fertiliser

Decided to go for a liquid fertiliser instead of the standard granular and it didn't disappoint.

LUSH AND GREEN

Love this product, made my new lawn from light green to a bright vibrant green in only two applications! Highly recommend. Purchased as part of the Lawn Lovers Pro Pack.

Activ8EXTRA Boosted liquid fertiliser

Nothing compares to this product. Especially now during growing season. Grass and plants have never looked better and stay healthy for longer.

Top Quality

I've been using Plant Doctor liquid fertilizers for some time now, and I can't fault them. They are of a high quality, and make my lawn look exceptional. I used Activ8 previously, and this new EXTRA seems to work even better!

Love it.

Seems to last forever with the dilution rate. Lawn loves it and plants love the overspray.

Great product

Very impressed, going to buy another 10 litres

give it the extra boot

This stuff is amazing. You will not be disappointed.

Amazing

Great product once again

Giving the grass some love.

I started using this about a week ago after adding Nature's Soil wetter to my lawn. Wow..... What a difference it makes. My grass in responding so quickly. Before it was hard to get it to do anything. This stuff is like gold in a bottle. I had some dead and dying areas of grass but now they are lush, green and filling in again.

5 star praise

First time taking on a lawn reno and with help and guidance from the plant doctor my lawn is looking amazing. This stuff is so easy to use with simple application instructions right there on the bottle you will get results in no time at the fraction of the price

Great adjunct liquid

Added this into my foliar program for the 2021/22 season and have been happy with it. It’s great to have a turf product with a bit more P and K for foliar application.

Great value !!

This stuff works out way cheaper per 100m2 compared to the stuff you can get from the green shed. Works a treat. Lawn has never looked better. Free shipping with orders over $59 is the icing on the cake.

Easy to use and cost effective

When used as per instructions adds excellent growth to all plants and lawns highly recommended

Activ8 Extra

I purchased this product for our Sit Walter lawn as wanted the grass to look more lush. The product worked almost overnight. This is definitely the go to product to use to put the greeness back into the grass.

Results boosted

This is a boosted version of Activ8mate - I was happy with the original but if you want some more push with extra nitrogen then this is the one to get.

Grow baby!

This stuff is amazing on lawns beautiful Green and lush Nature at its best

Activ8EXTRA Boosted liquid fertiliser

I feed this with the Seaweed Secrets to my lawn and plants and have gotten great results. Very economical as well. Great stuff.

Bang for buck

A great product from a great team.

Top quality - Super green

Top quality liquid fertilizer, produces a really nice green colour in your lawn. Supplemented by the liquid iron product - contains a safe proportion of nitrogen so you wont burn your lawn, you wont be disappointed with this product.

Works all the time!

This is my 'go-to' liquid lawn fertilizer that I use every month to keep my lawn in 'tip-top' shape! It's a well rounded fertilizer that can also be used on plants and trees and extremely beneficial during Winter given that granules don't do a good job in the colder weather. Highly recommend for all lawn lovers and rest assured Activ8EXTRA will differentiate a great lawn from a good one!

Converted

I use to always use seasol on my lawn, since being told about Activ8extra I've been converted and so have my mates that I've told

Can notice the difference

Great product, can definitely recommend this as I can see larger leaf size and faster growth on my indoor plants.

Big Help with my Reno

Activ8 Extra has been a big help bringing my Buffalo back from this years Reno!

A great Liquid Fertiliser

The results were fast and exceptional. Not only has it helped with growth but made the leaf seem stronger, encouraged root growth and has made the lawn one of the best in the street. Very happy customer.

Great product

Use this on my hedges and grass with excellent results

Amazing product

Got it in Ben Sims pack. Amazing product

Amazing results.

Got it in my Ben Sims pack. Absolutely stoked with the results

Great product

Active8mate is very good, this one is even better!

Fantastic Results

I have applied this product mixed with Plant Dr Humic Acid and Im seeing a noticeably healthier looking lawn. Plant Dr's service is second to none with a 2 day delivery free over $50, very happy customer

Great Liquid Fertiliser

Easy to apply product using a hortex sprayer and gave the yard a really good pop. I teamed this up with the granular fert, no issues and great colour. I get a lot of great comments from friends and family that turn up to the newly invigorated lawn!

Bit extra for the lawn

Loved the first active8mate, but this has a few extra goodies in it for that extra boost

Thick Turf

Since using this my turf has thickened up so well. It also has a very nice green colour to it. I have noticed I am not watering as much either.

This stuff is great

Just started using this product and applying as it sais on label and im seeing great results with it.

Really works!

I used this liquid fert during the recovery phase of my lawn renovation, and it really improved recovery time. Good for a rapid green up.

The boost you need!

In conjunction with my granular fertilizer, the boost of nitrogen really gives my grass the boost it needs

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Customer reviews

What customers are saying

5.0 from 0 verified reviews

So easy

Everything in the one bottle. brings my lawn back to life.

ConorB. Verified review

Activ8EXTRA

Just a very nice fertiliser for all plants and lawns for a nice little boost.Thanks Plant Doctor

Julius L. Verified review

Fantastic

I was recommended this by a friend to supplement my application of slow-release granular fertiliser. This liquid product is much faster acting and easier to apply. Highly recommend.

TomC. Verified review

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