Your plants will LOVE you for this. Grosafe's BioPower Organic Seaweed Flake in the 100 gram size is a natural super-food for plants, a bio-stimulant packed full of nutrients to boost plant growth and health without chemicals. I give all my plants a seaweed feed once a month and a seaweed soak before and after repotting (directions for use, below). I use about 1 gram per litre, so for me this 100 gram pack makes up to 100 litres. Superb value for money.

This is seaweed in concentrated flake form, that quickly and easily dissolves when added to water. Full directions below, but at 1 gram per 1 litre water this small 100gm pack makes up to 100 litres. Also available separately in liquid form in a 1 litre pack which makes over 500 litres.

What's in the bottle?

The dry flakes are a pure form of a marine seaweed called Ascophyllum nodosum, sustainably sourced and certified for organic use. The flakes dissolve easily in water and a little goes a long way. 

Why is seaweed so good for plants?

• Seaweed is a 'super-food' with over 70 beneficial minerals, vitamins and enzymes.

• It enriches soil and plant health.

• Helps protect from over-fertilisation.

• Boosts growth. 

• Is a natural source rich in micro and macro nutrients.

• Helps boost a plant's natural defences (what we think of as their immune system), and reduces transplant stress. 

• Also naturally high in plant growth hormones. Mainly auxins, cytokinins and gibberellins.

The BioPower brand in particular is a very high-quality seaweed (not all seaweed products are the same).

BioPower directions for use

How much seaweed do you use for indoor plants?

You don't need much. Just shake out 1 to 2 grams into the built-in measuring top (just under the 5ml mark on the top), and mix with 1 litre of water. Give it a good stir - the flakes dissolve really easily - and you're ready to feed. 

How often should you feed indoor plants seaweed?

The label advises feeding as often as fortnightly during the growing season, but a common method recommended for indoor plants is once a month, all year round (some people stop in winter). I prefer the monthly, top watering method myself.

How should seaweed be applied to plants?

You can top water, bottom water or use seaweed solution as a foliar spray directly on leaves. 

Top water: Dilute 1 to 2 grams BioPower per 1 litre of water (2 grams is the 5ml mark on the supplied measuring top). Stir well and top water. I prefer to drench well when top watering, until the substrate is thoroughly saturated, and water freely pours out the drainage holes. Drain well.

Bottom water: Dilute 1 to 2 grams BioPower per 1 litre of water and use as a soak. Put the pot inside a larger container, and pour seaweed solution into the outer container, until the seaweed solution comes up a quarter to half way up the sides of the inner pot. Soak for 10 to 20 minutes or until the top of the soil is damp. 60 mins max. Remove inner pot. Drain well. 

Foliar spray: As effective as this, I'd avoid spraying with seaweed indoors. Even once diluted, the water will be brown and would need to be cleaned off any surfaces it splashes on so it doesn't leave a mark. I would spray outdoors and spray lightly. Just one light coating of weak seaweed solution will do the job. I use a half-dose, about 1 to 2 grams of BioPower seaweed flake per 2 litres of water in a fine-mist spray mister. As with any foliar spray, best applied in the morning on plants that won't be in direct sun, so leaves get a chance to fully dry. Check leaves are dry before returning to a full-sun position. Spray one light layer only.  

For outdoor plants, use 10 grams (2 caps) per 5 litres of water, and water in or apply with your sprayer. See the label for application rates for pip fruit, stone fruit, citrus, grapes and berry fruit, vegetables, roses, lawn and turf.

How to use seaweed when repotting

Repotting is like major surgery for plants. Seaweed helps reduce transplant stress and aids root recovery, ideal to help plants handle the stress of repotting.

24 to 48 hours before repotting, give the plant a seaweed soak as per the bottom watering directions above, for 60 minutes maximum. Directly following repotting, give the plant another seaweed feed, either top water or bottom water, so the new substrate and roots are saturated with seaweed solution to help with recovery.  

Does seaweed replace fertiliser?

No, but that's a common misconception. Seaweed is not a complete and balanced fertiliser. It doesn't offer adequate levels of all the nutrients your plants need. Think of it as a growth stimulant or health booster, more like a vitamin and mineral supplement, rather than a complete meal. 

Can you mix seaweed with fertiliser?

Yes, for most fertilisers you can, however it's best to check before you mix them together. If you're unsure, just save one water per month as a seaweed-only feed, and for the rest of the month, use your fertiliser as usual every time you water, rather than mix-feeding. 

Link to download the safety data sheet >