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!
Perfected over billions of years, nature always provides a solution far simpler and more effective than anything we can dream up in a whole lifetime.
Every day with a hiss and a foam our beaches wash up a gift for gardeners – tonnes of seaweed bursting with nutrients and what’s more it’s free. Every year the council for Altona beach spends around $300,000 to remove it, $300,000 to beautify a beach from seaweed! It is either dumped in landfill or washed(!) and returned to the sea! I discovered this when I was researching to see if it was legal to gather seaweed in Melbourne, I’m going to go ahead and assume yes on this one.
A small percentage is now being converted into liquid fertiliser, which is a start, but wait a second…why does it need to be commercially processed to turn it into a liquid or dehydrated powder and bottled in plastic and delivered to a nursery and purchased for $10/L and diluted and sprayed on your garden and the bottle thrown in the recycle bin? Why do all that when it is the most divine mulch you’ll ever use and all you have to do is spend a day at the beach?
Now that sounds like an excellent way of saving time, energy and money!
WHY I USE SEAWEED MULCH
2.5 years ago we started our first vegetable garden. My mother gave me a jar of powdered seaweed for out little 1mx1m pallet garden, part of a no-dig recipe sprayed between layers of dry straw. Then Permaculture crept in and with it shiny tomes raving about seaweed tea, how could I resist making my own brew? The result, well…it was smelly, honestly it stank like a sewer! And some mosquitoes got in and that was the end of that idea! There had to be an easier way! There was – it was simple, just rinse it and spread it on the garden beds, done, easy. When my other quizzed me on it, I didn’t really have an answer, mulching is good, seaweed is good so don’t they make a perfect pair? I retaliated with research and was pleasantly surprised that it was actually a brilliant thing for your garden!
AND WHY YOU SHOULD TOO
nutrient rich and the nutrients are easily absorbed by plants
trace elements are transferred to the plant and its fruit, more nutrient rich for you too
free and easily accessible and free, a beach holiday once or twice a year is all you need
contains very little salt, the sand is what makes it too alkaline and this can be washed off
soil conditioner, healthier soil
plant conditioner, healthier plants
make plants more resistant to disease, shares no diseases with land plants
deters pest like snails and slugs
keeps soil moist – less watering (less heat stress)
insulates the soil – cool in summer, warm in winter (makes plants more frost resistant)
suppresses weeds, contains no land weed seeds
WHAT’S IN SEAWEED?
all major and minor plant nutrients
all necessary plant trace elements (over 60 in total)
alginic acid
vitamins
auxins
two or more gibberellins
and antibiotics
No wonder they say it’s good for humans to eat too!
When I read this list I’ll admit I wasn’t even sure what some of those things were, but it’s all pretty straight forward once you can get your tongue around the words!
These are all essential for plant growth and health, they are a plants food and drink.
NON-MINERAL NUTRIENTS
(hydrogen, oxygen, carbon) are provided by air and water, converted using the sun’s energy (photosynthesis) into starches and sugars. However, all the other required nutrients can be provided by seaweed.
MINERAL NUTRIENTS
dissolve in water and absorbed through plant roots. When soil minerals are not in balance plants become sickly. This is exacerbated when the same crop is planted year after year, depleting the soil of specific elements.
Just as iron in vegetables (non-heme) can be harder to absorb than iron from meat (heme), the minerals you are adding to your soil need to be in a form that is usable for the plants otherwise it won’t be absorbed.
Trace elements can be made available to plants by chelating (combining the mineral atom with organic molecules so they cannot form insoluble salts the plant cannot absorb).
Seaweed contains starches, sugars and carbohydrates that possess such chelating properties, so all the lovely nutrients it contains are available to the plants which need them.
VITAMINS
Soil depletion has adversely affected the vitamin and mineral content in our fruit and vegetables. Healthier soil rich in vitamins and nutrients leads to a healthier product for us to eat. Vitamins contained within seaweed include:
vitamin C
beta-carotene, fucoxanthin
B1 (thiamine), B2 (riboflavin), B12
pantothenic acid, folic acid and folinic acid
vitamin E (tocopherol), vitamin K
other growth-promoting substances
AUXINS & GIBBERELLINS
Encourage the growth of more cells as well as enlarge, stimulating the growth in both plant stems and roots.
SOIL CONDITIONER
The alginic acid in seaweed , whether it be fresh, dried or liquid, improves the soils ability to retain moisture and hold together. This helps to form a good crumb structure: large particles providing drainage and air movement and small pore spaces between to hold water and plant nutrients. This means in times of heavy rain, seaweed can improves sloping, silty, sandy soil so that seedlings and nutrients no longer get washed away. Conversely when it is very hot the soil will be slower to dry out.
BACTERIA & NITROGEN
A good crumb structure stimulates growth of root systems as well as the activity of soil bacteria. The good bacteria secrete beneficial polyurinides that further condition the soil as the seaweed decomposes. The seaweed should be applied 3.5 months before the plants require an increase in nitrogen. This is because bacteria require nitrogen to break down undecomposed vegetable matter into simpler units, leading to a temporary reduction in nitrogen in the soil. After this latent period the overall amount of nitrogen in the soil is dramatically increased so it is beneficial to time this with for instance the fruiting of a tomato when the plant requires a little something. However, if a pick-me-up is required the nutrients in liquid seaweed are available at once and this can be used as a foliar spray absorbed directly through the leaves.
ANTIBIOTICS
Plants mulched with seaweed develop a resistance to pets and diseases. It is believed that soil fungi and bacteria produce natural antibiotics which control pathogen population reducing the likelihood of a number of plant diseases. The concentration of organic matter/seaweed in the soil increases the production of these antibiotics.
True Spring Preparation – Temperate Climate – Southern Hemisphere: September & October – Northern Hemisphere: March & April
FEVERFEW – GOOD COMPANION PLANT FOR HERB BORDER – ENHANCES THE GROWTH OF PLANTS AROUND IT
The wind began to whirl, but it was delicious, it was warm. It carried flower petals, dandelion seeds and the promise of rain.
Spring has come, there is no time to catch your breath, the gardening marathon begins.
Like bright, juicy drops of rain raspberries start to slowly ripen, then in a matter of days become a deluge of fruit. Strawberries too are ripening and all at once everything that was quietly growing over the cool months bursts into flower, even those things you’d rather not like broccoli, coriander and celery, but the chickens are please for these sweet offerings.
We’re getting our first hot days, climbing towards 30 degrees and with the first appearances of the predator insects we know we are safe at least for a few months until the more annoying flies and mosquitoes start plaguing us.
It’s our last chance to get the garden bed ready before the tomatoes get planted out in High Summer. Mulching, weeding, pruning and after that planting out some companions to lend some shelter when it starts to get really hot.
weeding
If vegetable seeds are slow to germinate, so are the weed seeds. If you didn’t do it last month this is a great time to pull out those pesky grasses and nutrient hungry fiends and mulch heavily to prevent them from springing up again. Soon with added sunlight and water they can get out of control.
Some “weeds” I leave, like dandelions which are edible and are a good companion for tomatoes as they exude a little something that helps the fruit ripen. Clover is a nitrogen fixer, absorbing nitrogen from the air and putting it back into the soil. There is no use pulling out something that is useful and leaving bare soil for something nastier to take root, better to leave it until you have a seedling in hand to replace it with.
pruning
The herb border around my garden bed has really sprung into life this season. Mint has sent out runners like a web through the garden bed and the Feverfew has grown enormous. True Spring is a great time to take cuttings and divide up your herb border, keeping it under control and if you can’t use those new plants there will be enough time for them to get over the trauma to be gifted at Christmas.
pest control
Everything is sending out juicy, sweet shoots that snails can’t resist. It’s not hot enough for them to retreat and all it takes is a storm for them to pop up under every leaf. They must be controlled before you plant out your seedlings. A week of beer traps and night time torch hunts with your work boots on will; keep them in check.
A strong smelling herb border with spiky leaves will mean less placed for them to hide during the day, these include Winter Savory and Thyme. I have learnt to my horror that edible violas are about the worst thing to grow on your garden edge, the tender, multitudes of leaves and flowers beautifully cascading over the edges the perfect snail mansion and nursery. I am trimming and pulling these out straight away!
mulching
The weather is still quite variable hot and dry one day, freezing and rainy the next, a good thick layer of mulch around the base of all your plants will help keep a balance of warm and damp to prevent your plants going into shock.
Remember snails like to hide in mulch so keep it fine and check each night for the slimey sneaks. More about mulching in my next post!
These two months are when you should really try and sow EVERYTHING you want to occupy you garden until Spring comes again next year, even things like silverbeet that you can plant later can be planted now and kept going all year with dedicated picking, watering and mulching.
This is the time to get the seedlings well established as High Summer will
knock tiny plants to the ground with its sizzling sun and bruising winds.
By Christmas there should be no bare earth in your garden beds, your plants crowded with little soldiers selflessly shading their neighbour and being shaded in return.
Afterall this is not meek and mild Europe where things can flutter in gentle summer breezes, spaced out rows, kissed by fairies and the like. In Australia, if snails don’t go down the line chomping up your progeny then our unfiltered, ozone depleted rays of suns will finish off the job. Plus won’t it be so much more relaxing knowing that your garden can be left for a week or two over Christmas, planting finished and resilient enough to take a few 40C days. (Hopefully you have a nice neighbour check in every 10 days or so)
planning
It’s hard to not be overwhelmed after a long winter of lethargy. I like to organise the seeds I’m going to plant for the season into glass jars with seed tags made out of plastic milk bottles. Clear plastic is hard to read and cardboard crumples with water, so I’ve found milk bottles best. The glass jars make it easy to see the seed labels and keep them dry if left outside on the propagation table.
I use to be precious with my seeds, sowing only a few at a time, but with a shoebox full of expiring packets, I’ve learnt is far easy to sow an entire packet at a time and save the fresh seeds for the next year.
with your overflowing recycling bin and a sigh of shame that you are not doing enough to be sustainable. But be warned what begins as a wholesome notion to re-use can quickly escalate and before you know it you’re that crazy lady
looking at the neighbours’ bins with a twitching desire to rummage through them for treasures.
It’s best to dial it back a notch at this point and stick to finding alternate job descriptions for your own rubbish, we can’t all be Tiffany Sedaris.
And besides when you have five housemates you have plenty of material to keep you busy.
The youngest drinks at least one 3L plastic bottle of orange juice a week, two if there are no bottles of coke in the fridge, that’s over 52 binned a year!
They might be recycled into the latest in green bag technology or a jazzy promotional hat, but I’m sure that comes at a huge energy cost. It seemed like a waste, so I started thinking about what else I could do with them…
Autumn came and it brought with it a slimy army of snowpea killers! I sliced the bottom off the juice bottle and dug it into the soil to became an impenetrable snail guard. The peas climbed upwards and their salvation became their prison as they clawed at the closed bottle lid. I set them free with a twist and the snails savaged them with a crunch.
I retaliated, slicing the top off the bottle as well and added another, then another bottle, stacking them to form a tower, the peas grew tall and strong and when they were released the snails turned up their nose at the strong tough stems and didn’t think to crawl upwards to the tender shoots.
The weather cooled and the bottles doubled as greenhouse to encourage young lettuces to be sweet while their unbottled neighbours grew world weary and bitter.
And now we come to the current day, the weather has mellowed and soon I will need to start planting my tomato seeds and I thought…
tomatoes despise being transplanted almost as much as they hate the cold, dry soil and wet feet!
Coupled with a general lazy attitude toward fiddly potting on, the bottle greenhouse was born!
Now we finally come to my experiment (Don’t you hate it when people take ages to get to the point? Ha!).
The “pot”
is a bottle with the top and bottom removed and is filled 3/4 with potting soil, then a piece of damp newspaper and 1/4 of seed raising mix. After this has settles the seeds are planted in the top in the more friable, low nutrient soil, when the roots are large enough to break through the thin paper they get a boost from the more nutrient rich potting soil.
A half bottle cut length wise is
the water “tray”
at the base. The “pot” is placed in the “tray” before it is filled which prevents the soil from falling out. Then from the top the soil is well watered until the water pools in the tray. While the seed settles the soil moisture levels will stabilise so it is neither too dry or too wet, if it is hot additional water may have to be added to the tray before planting. When the seeds go in the top should be gently misted and the tray filled with water.
The seeds won’t be washed away by overenthusiastic water spray and the water in the tray will slowly wick up through the soil to the developing seedling’s roots as it needs it.
Even it hotter weather the tray doesn’t have to be filled everyday so you are free to leave your nursery for a long weekend beach break without coming home to crispy reminders of what could have been. It will also encourage deep roots, which are preperable as shallow roots are more likely to dry out when planted in the garden.
A bottomless bottle acts as
the “greenhouse”
in cooler weather it keeps heat in and as it warms up it prevents too much moisture loss. Ventilation is important as the soil can get mouldy so the top can be left off. If pests are a problem the lid can be left on and small ventilation holes pierced around the bottle neck, too small for a slug.
When it comes time to transplant the “pot” can be gently buried, the roots undisturbed grow out the bottom into the soil with no transplant shock. The tomato experiment? More about that soon…
