We know why seaweed mulch is a good idea, but what’s the best way to use it?

Now you know the why, here is the how.

Before the blaze of summer can tempt you to take the plunge, how about a springtime stroll along the water’s edge? When you roast in the height of the hot weather so will your garden, now is the time to prepare ahead!

COLLECTION

It’s easy to be greedy when you know how good seaweed is for the garden, but only take small amounts and not all from the same spot. You don’t want to devastate the delicate beach ecosystems!

I make an outing of it, carrying a small bucket and strolling along, taking only palm sized pieces. I make sure there are some decent footprints behind me before I pick up another piece. These smaller pieces are also much, much easier to handle than lugging a great frond of kelp along the beach, the finer stuff makes better mulch anyway.

It’s better to gather seaweed ‘mid-beach’ because it is drier than that at the ocean’s edge and can be shaken free of sand.

Believe me, having transported wet seaweed home in the past, the great sopping, stinking mess of sodden seaweed is a headache not worth repetition. Conversely, anything too high up the beach has been there too long and may contain land weed seeds from the dunes.

WHEN TO APPLY

As it takes 3.5 months to release nitrogen back into the soil, don’t apply just as you plant out your prize tomato plants. The sudden decrease in nitrogen will stress them out.

Time it so when they start fruiting in mid summer they get that extra boost. This is beneficial not just in the case of tomatoes, but many fruiting plants as too much nitrogen in the soil early on can encourage vigorous leafy growth at the expense of flowers and therefore fruit!

So True Spring is the perfect time to apply seaweed mulch, just as you are sowing your tomato seeds, come the end of High Summer when the first fruit is ripening they’ll be crying out for the extra nutrients.

HOW TO APPLY IT

As simple as soak, crush and spread

As I mentioned in my post Seaweed Mulch Explained, seaweed itself is not particularly salty, it’s the sand that is very alkaline. So when I get home from the beach with my bounty I just shake the sand out and give it a good soak in a bucket to get any residuals off. Then I lay it in the sun to dry out again so I can crush it with my boots into a finer stuff.

This is optional if the pieces you picked are already quite small, but there is a satisfaction akin to jumping in puddles in the crunch this makes. The seaweed can then be sprinkled around each plant, carefully avoiding their stems and thoroughly watering it all in. In a month the companion plants should have filled in the gaps and any bare soil can be covered with a ‘chop and drop’ of any unruly herbs from the border.

COMPOST

Of course if you don’t apply it directly as mulch you can simply add it to your compost. While land plants require cellulose to thicken their walls to stop them flopping over, seaweed is low in cellulose as it’s supported by water and this means it breaks down really quickly in the compost heap. Sluggish composts often lacks nitrogen so seaweed is an excellent compost activator. It helps break down high carbon materials in the compost such as fallen leaves, newspaper and fruit waste. So if you have any extra seaweed lying around why not add it to the pile.

SEAWEED TEA

Another option is to soak it in a container of water for several weeks, then dilute a small amount in a full watering can and spray on or around struggling plants. When applied the nutrients are available straight away, unlike when mulching so it is excellent to pick up unhappy looking plants. It is very important to add oxygen to the brew by agitating it three times a day or it will become anaerobic (horribly stinky). This entails swirling it with a trowel until it forms a vortex to keep it aerobic. I must admit this is what drove me to using it as a mulch. A barrel of anaerobic seaweed ooze is just about as unpleasant as it sounds when it’s been soaking a while. Don’t even get me started on the visceral reaction I had when some of it spilled onto my pants and then began its merry journey downward into my boots. So I council if making a tea, make it in something small, but… when you can be as lazy as collect, rinse, apply, why bother? Your plants should never look sad if you have properly made their bed!