Compost and Mulch - Do We Know the Difference?

Differences

Do we know the difference between compost and mulch?

I admit that I get a bit confused which is which as definitions can be very vague. I tend to use them both in the same way, just putting them on top of the soil and letting the worms do the work.

There is a difference though and I was chatting to Rosie Harding this week who is a bit of an expert in the field.  Rosie and her husband Peter have regenerated a piece of degraded land in Goa, India, into an abundant and productive kitchen garden and food forest. I asked her how they differentiate between mulch and compost and why it’s an important part of their garden.

What is Compost?

“Compost is decomposed organic material”, Rosie tells me. “It is person made, commonly using a mix of kitchen scraps and wet and dry garden leaves, grasses and trimmings. When it is ready it is a deep dark brown, almost black, feels moist and crumbly to touch, and does not smell bad, but has an appealing earthy smell.

At its simplest, compost is a pile of organic matter that will decompose by itself in as little as 18 days but can take many months, depending on the content and season. At its most organised, it is a recipe blend of wet and dry materials, a specific ratio of nitrogen and carbon.

When organic matter decomposes naturally on the forest floor in nature, it is called humus.

Benefits of compost:

• Increases the soil’s ability to both hold moisture and drain better all at the same time.
• Nourishes your plants.
• Adds important microorganisms and fungi to the soil (which are part of an important and often overlooked soil foodweb that is actually what is feeding your plants)
• Improves soil texture.
• Has insulating qualities against heat and cold.
• Helps to break down the mineral elements of your soil (ie pebbles) and contributes to making those nutrients available to the plants.
• Compost can be used to make suitable potting mix to germinate seeds.
• It can be easily side-dressed into the soil next to a plant that may require a “nutrition boost”.

What is Mulch?

“It is any type of material that is spread or laid over the surface of the soil as a protective covering. It can be in the form of living mulch, growing in and over the ground, or a layer of mulch material on top of the soil, for example dry leaves or straw.

Benefits:

• A thick layer (think at least 2 to 3 inches) of dry leaves or straw will immediately cut your watering requirements by 50%, from Day one.
• Protects the soil underneath from the harsh sun and lashing rain.
• Suppresses weeds.
• Reduces erosion.
• Provides habitat to frogs, lizards and other garden friends.
• As it breaks down, it provides food to the microorganisms & fungi already present in the soil.
• In the case of living mulches, which can also be in the form of “green manures”, the roots are also benefiting the soil, helping with aeration, and with both drainage and moisture retention equally.

Why the confusion? “You may find references of compost being used as mulch, especially in Ireland as it is a temperate climate. Here in the tropics a protective layer of mulch is really important for retaining soil and protecting it from the elements such as scorching heat and torrential rain.

A common mistake is to dig mulch into the soil, instead of placing it on top of the soil. This will cause a temporary nitrogen deficiency as the nitrogen in the soil is used up breaking down the carbon of the un-decomposed or only partially decomposed mulch.

A tip for those with smaller spaces in urban and suburban areas, including those with potted and terrace gardens. When people in these areas ask what the best thing that they can do for their soil is, the answer is always Mulch, Mulch, Mulch.

Given the huge quantity of leaves that are burnt or otherwise disposed of every year as part of “tidying” homes and gardens, it’s possible to rapidly collect large quantities of mulch. As much as you may need for a few pots, and way more for those that can use even larger quantities. And you can never have too much mulch. Mulch is absorbed extremely quickly into soils that are poor in organic material, and over time, as the organic material builds up, the rate slows. If ever you really do get your hands on “too much mulch”, then you can compost it.” Rosie concludes. see their page here

As we are on the subject of differences, did you know these too?

Briefly

Differences: Hay and Straw

Hay is a crop that is grown specifically for the purpose of creating hay, while straw is a byproduct of different kinds of crops. Hay is geared toward being a nutrient-rich food for livestock, while straw is more often used for bedding instead of food. Straw also has a wide variety of uses, for everything from a compost pile to an energy source

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Differences: Cacti and Succulents

What define true cacti are areoles. Areoles are what spines, spines, branches and flowers may sprout from, and all cacti have them, while succulents don’t. Areoles are not hard to find – they usually look like small, fluffy, cotton like lumps on the body of the cactus.

So, the next time you look at a succulent, look to see if they have areoles. Then you will know for certain that it is a cactus, or not. 

Remember though, there are exceptions to every rule.

Tasting Better after Frost - And the Plantpot Heaters are Back. Do they work?

 Plant pot heaters, do they work..?

We didn’t really get a frost last year. I agree we had a few mornings that were white over on the ground but that’s about all. I say that, not because I was looking at my pinecones or analysing weather data, it’s because of my own observations in the garden. My frost tender plants survived outside with no protection, I’ve mentioned before about my cacti and geraniums surviving without any sign of frost damage. The frostless weather also meant that a lot of slugs were free to multiply; it’s been one of the worst years for slug damage for that very reason, chickens are happy though.

The frost also plays a big part in improving the taste of certain vegetables and although we only got the touch of frost last year, I am sure it was enough to make the broccoli taste a bit sweeter

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Plants taste better after a frost

Brussels sprouts, kale, mustard greens, cabbage, parsnips, carrots, celery root, beets, turnips, rutabagas(swede and turnips) ,Kohlrabi (German for cabbage turnip) and oca (New Zealand yam) all taste a bit sweeter after frost. Leeks and celeriac also benefit.

Why is that?

When really cold weather happens, carrots parsnips and other root vegetables convert some of their starch stores into sugar. They do this to keep the water in their cells from freezing, and it works in the same way that putting salt on a road keeps it from freezing over. When another substance mixes with cold water, it makes it harder for enough water molecules to reach the surface and freeze there. This lowers the freezing point. The cells inside a carrot might have icy-cold water, but that water won't turn into ice, which is a good thing as the formation of ice crystals within and around a cell can destroy it. 

There’s a more technical explanation if you want to impress your friends. “Sugar accumulation in living and non-living tissues during winter in cold-hardy plants has long been observed and is thought to be important in cold acclimation because it increases viscosity, which reduces ice crystal formation, helps stabilize membranes by binding to the free phosphate groups of membrane lipids, maintains respiration in living cells, and allows cell metabolism to recover after freezing." Just incase anyone asks!

The resulting increase in sugars makes them more palatable for a lot of people. This post-freeze deliciousness will be true of any of the vegetables that can survive a hard frost, including the ones I have mentioned earlier such as broccoli, kale and celery. There are a few exceptions. Leeks for example produce their sugars after dormancy and frosted potatoes can cause carmelisation when they are being cooked which turns your spuds brown. I can cope with that and I for one am hoping for a few harsh frosts this winter. Lag your pipes!

Heat your home with a tea light and plant pot -NOT

There are a lot of youtube posts and facebook entries popping up promising to “Easily Heat Your Home or Greenhouse Using Flower Pots and Tea Lights”. The idea is that you upturn 2 terracotta pots, of different sizes, one inside the other and space them out with washers and bolts. These are put on stands to allow air flow and then tea lights are put underneath to create a “thermal heater” More and more elaborate designs are coming out but they all have the same level of efficiency.

This concept has been around a while and seems to come back every autumn as the weather gets cooler. Here’s an explanation of the science behind the phenomena, and you can decide if it works for you.

A naked candle puts out a very small amount of heat into a room (approximately 263 BTU/h or 77w), so you would need 19 candles burning to equal the typical 1500w room heater.

But a flower pot makes it put out more heat, right?

No, a flower pot converts the candles convective (air) heat, to radiant (body) heat. It also shifts the time period, as the clay takes a while to heat up, and also to cool down. If you are sitting directly next to the pot, you would feel warmer, but the room would take longer to heat up. Both methods would bring the room up to the same temperature.

19 candles would incur sooting and corresponding lung issues, so there will be a cleaner heating source. For comparison purposes, a 77 watt light bulb running 24 hours per day costs €0.18 (at €0.10 / kWh). That’s cheaper than buying candles, a whole lot safer to use, and better for your health. You could put it in a flower pot to give the impression of candles burning if you like; I’ll put on a jumper and wrap my plants up with horticultural fleece.

Invasive Ground Cover Plants

Expectation versus reality with the Houttuynia

When a piece of ground is difficult to get to, I usually start looking for ground cover plants. At first thought it seems to be a good idea, but give the plants a few years and I am trying to beat them back with a stick as they try to invade the rest of the garden.  I have one main offender in the garden and I didn’t even plant it myself, the ‘Houttuynia cordata chamelion’. It turns up everywhere and will even grow in water, check out the image to see the difference between expectation and reality.

Groundcover plants

I do realise the virtues of groundcover plants and they can make the garden an easier place to tend, but like all plants growing in a controlled environment (the garden) they will need to be kept in check. Most ground cover plants don’t know when to stop and have no intention of keeping to their allocated space. The plants either throw out runners, seeds, bulbs, offsets and most have the ability to engulf and destroy any other plants in their path as they spread.

Invasive plants aren’t confined to ground cover either. We have all manner of climbers which will happily engulf the house, from ivies to Russian vines and passionflowers. Trees can be a nuisance too. Leylandii doesn’t even need an explanation as I am sure you are overlooking one as we speak. Then there are poplar, sumach and cherry trees which will happily throw out offshoots along the lawn and can be very difficult to remove.

Bamboo, sedges, reeds and grasses can also take over needing a lot of annual tending to. I have a couple of large fish boxes planted up with bamboo and have no intention of letting it out into the main garden, the same goes for my mint, soapwort, anaenome and chinese lanterns. They all have their own containers.  

Perennial plants can become invasive too and will probably need dividing and replanting when the clumps grow too large. Even raspberries and blackcurrants can get out of control when not kept in check.  Horseradich and artichokes can get out of hand in the veggie patch too. 

Precautions

It only takes a neglected season for some of the plants to take over.  If some have got out of control there are a few things we can do. Hoe off or hand weed seedlings when small and try to remove dead flower heads regularly to prevent seed dispersal. Some lovely plants can throw out thousands of seeds in one go. chives, fennel and Verbena bonariensis to name but a few.

Digging out unwanted plants may work for a while, but is only likely to be a temporary solution. Suppression under black plastic or weed membranes, thick cardboard and mulch is an alternative but again could take several growing seasons to be effective. 

Caution is needed removing the plants too. When disposing of invasive plants and their seed heads it might be an idea not to put them into the compost heap, as this is unlikely to reach a high enough temperature to kill off seeds, tough roots or underground stems. Instead, place them in the municipal green waste, as this is composted on an industrial scale, where tough weeds should be killed off. Burning may also be appropriate, but you might have to pick a day when the smoke won’t annoy the neighbours.

It’s not all doom and gloom though with groundcover. Some plants can be quite well behaved and if you have a garden (like me) that is allowed to run pretty wild, they are a very welcome addition to the planting schemes we design. I have loads of lawn chamomile growing and it’s spreading at quite a fast rate into the gaps and crevices of the paths. Strawberries do pretty well covering the ground in the veggie patch too. 

There are categories for ground cover. We have:

Mound forming and prostrate shrubs

Deciduous shrubs such as: Cotoneaster horizontalis  and Potentilla fruticosa ‘Manchu’.

Evergreen shrubs include: Berberis candidula, Calluna vulgaris, Cotoneaster,Ericas which do really well in our soil,Gaultheria procumbens ,Hebe pinguifolia ‘Pagei’ ,Juniperus sabina ‘Tamariscifolia’ and Taxus baccata ‘Repandens’.

Perennial plants

Herbaceous perennials include:

Alchemilla mollis ,Bergenia ‘Morgenröte’,Cornus canadensis and Geranium macrorrhizum ‘Ingwersen’s 

Evergreen perennials include: Epimedium perralderianum,Persicaria affinis ‘Darjeeling Red’

Creeping, suckering, spreading and thicket forming plants

Herbaceous: Ajuga reptans ‘Caitlin’s Giant’,Galium odoratum

Evergreen, loads to choose from including: Euphorbia ,Hedera colchica ,Mahonia aquifolium,Pachysandra terminalis ,Vinca minor

Listing types of plants such as this is all well and good but the best thing we can do is pop down to the garden centres to see what is available, and have a nosey at other gardens taking notes.

Autumn Bulbs,Corms and Tubers

 
                                                              Crimson Flag Lily

Albert Camus summed up this time of the gardening calendar with a quote.  “Autumn is a second spring when every leaf is a flower.”  There are so many beautiful colours about in the late sunshine. There are also plenty of delightful colours in the flowers that grace our beds and borders at this time of year.

Perennial plants continue to throw out lovely hues. Red-hot pokers are sending their toned reds and oranges into the air and tubular Penstemon are a delight to see waving in the wind. Large multi coloured annual dahlia flowers flop and hang in there as the threat of the firsts frost come upon us. You can see why dahlias are so popular for council planting as they have a really long flowering season. Asters are similar and can last even the mild ground frosts in the evenings.

It’s not only perennials that delight in autumn. There are a lot of bulbs coming up now that add to the myriad of colours. 

Bulbs, Corms and Tubers

Crocus

Crocuses are some of the best known of the autumn bulbs for the garden. These jewels of the autumn force their blooms through the fallen leaves to create a festival of colour, even before their foliage appears.

Dahlia

Slightly different from the annual types, these striking blooms of these tuberous plants start to open in summer, but are at their best from August to September, bridging gaps in borders as other perennials begin to fade.

Nerine

One of the hardiest autumn flowers.  A bold block of cerise pink nerine flowers make a breathtaking sight on a bright autumn morning. These South African plants are unscathed by cold weather and surprisingly easy to establish.

Crimson Flag Lily

The most common one around here is the 'Major'. This hardy and vigorous clump-forming perennial grows to 60cm in height, with grassy light green leaves and erect stems bearing lax spikes of up to 10 crimson-scarlet flowers 5-6cm in width, from late summer. They are similar to nerines in their growing habits and the fact their origins are from the South African plains.

Sternbergia

Similar to Crocus, Sternbergia make excellent bulbs for autumn colour at the end of the year. They love full sun.

Gladiolus

The tall, slender stems come into their own in early October. They will need a bit of TLC though and be dug up before the hard frosts so not everyone’s favourite.

Begonia

Tuberous Begonias are the most glamorous bulbs for adding a bright colour accent to shady patios. Their beautiful flowers are produced over an incredibly long period, from summer all the way through to the first frosts in November.

Cyclamen

Cyclamen are actually corms and are very useful for brightening up those dry shady areas beneath trees, where other plants struggle to grow and make excellent woodland autumn bulbs. Cyclamen hederifolium is the usual choice for autumn flowers .For later flowers the Cyclamen ‘coum’ is often used.  Braving the cold winter weather as early as January, the pretty pink blooms emerge ahead of the foliage which later forms a carpet of silver-marbled leaves., Cyclamen coum enjoys a damper soil than it’s cousin, thriving in moist shade beneath trees and associating beautifully with snowdrops.

Snowdrop

With so many different species and varieties to choose from, the snowdrop has gained almost fanatical popularity and galanthophiles pay enormous sums for a single bulb. But you don’t need to break the bank to enjoy these winter beauties. Try the Galanthus elwesii, the giant, honey-scented snowdrop or Galanthus nivalis ‘Flore Pleno’, the double flowered variety. For natural looking drifts, gently cast the bulbs across the planting area and plant them exactly where they land.               

Winter Aconite

These cheery winter aconite bulbs produce golden, cup-shaped flowers surrounded by a green collar of leaves - just like buttercups in the depths of winter! Not for the tidy gardener - Winter Aconites almost demand to be grown in bold natural drifts where they can be left undisturbed to die back naturally in spring. They love a moist soil and a shady position, so they’re perfect for under-planting among woodland trees