We don’t often think about feeding lawns. Watering them, sure. But fertilisers are for food crops … right? Well, your garden freshens the air, raises your property value, and probably soothes your soul – the grass is so calming!
And if you want that grass to stay green, vibrant and healthy, you should know how to choose lawn fertiliser. So let’s get started with the lesson!
How to Choose Lawn Fertiliser
Tip #1: Check the Nutrient Content
Lawn fertilisers have three main components: nitrogen, phosphorous, and potassium. These elements are mixed in varying ratios, depending on your plant needs. Nitrogen helps leaves grow quick, thick, and green. Phosphorous helps with root development and nutrient absorption from the soil. Potassium helps with transpiration, fruit, and flower formation.
If you check the product packaging, you’ll see the initials NPK. This is often followed by three numbers separated by colons or dashes. For example, you might see 15:5:10 or 7-7-7. This shows the percentage of nitrogen (N), phosphorous (P) and potassium (K) in the product.
And no, it doesn’t add up to 100% because the rest of the bag is filler. Also, note that organic fertilisers have lower concentrations of macronutrients. They can get as low as 4:3:4. So if your soil lacks any of these elements, pick a fertiliser filled with what your lawn is missing.
Tip #2: Look Out For Supplements
A lot of us are anti-weed-and-feed. So while those combined fertiliser-weed-killer products are popular, we recommend buying lawn feed and herbicide separately. Even if you plan to apply them the same day. That said, some fertilisers still have herbicidal properties. Iron, seaweed, and sulphur are excellent at killing off unwanted moss without hurting the grass.
Seaweed isn’t specifically a fertiliser – professionals describe it as a soil improver. But it’s still packaged as seaweed feed, so yes, you’ll find it in the plant food section. It contains multiple micronutrients that can benefit your lawn. These include barium, zinc, boron, copper, cobalt, iron, iodine, manganese, selenium, molybdenum, vanadium, and nickel.
Tip #3: Consider the Format
Lawn fertilisers can be liquid concentrates that need to be deeply diluted. It’s risky to buy these if you’re a layman because you could easily hurt yourself or overdose your lawn. These fertilisers are so pure that a single 5-litre bottle of concentrate can be diluted to last 15 years.
Liquid fertilisers – once you mix them right – are the easiest to use. Grass absorbs them almost instantly but you have to repeat the treatment twice a month (or more). They’re diluted with water, but you can also buy solid powder lawn feed. Mix the powder with warm water to help it dissolve more efficiently. The third form of fertiliser is dry fertiliser.
It’s granular and needs to be applied on a damp lawn. The moisture helps the granules stick to the blades of grass and cling to the ground so they can seep into the soil. Dry feed sits longer in the soil before you need a refill. You can apply it every two to three months as needed.
Tip #4: Pick Organic or Synthetic
In the food and beverage world, vegetables, fruits, (and meat) are organic if they were planted, raised, or reared without chemicals. For beef, this means the cows were grass-fed and were probably reared free-range. They might be corn-fed too (that’s maize to us).
But in the lawn world, going organic means you have to use manure or plant-based fertilisers like seaweed. Other examples are fish, bone meal, and compost. Control lawn pests using natural methods like frog-repelling plants or carnivores with roots and shoots. These plant predators (like butterwort) eat bugs so they protect your lawn while keeping it truly organic.
Organic nitrates include blood meal, anything fishy, and kelp (seaweed). Bone meal is rich in phosphorous while Greensand is a good potassium brand. But if you’re fine using synthetic fertiliser, pick up the right chemical mix from a trusted agricultural store or landscaper.
Tip #5: Pace it Right
Quick-release fertilisers can feel like a magic potion because you’ll see the difference in weeks! But you may end up using more of the product because fast-growing lawns are also fast-drying lawns. They didn’t have time to develop properly so they’re more susceptible to weather, pests, and diseases. So … does that mean you have to stick with slow-release?
Not really. Slow-release fertilisers (e.g. compost) are best for winter months when your grass is dormant and covered in snow. This slow-release lets your grass gradually grow and thrive beneath sheets of ice and burst out in bright, beautiful blades when winter is gone. But the wait can be frustrating in other seasons, so consider a mix of slow and fast-release fertilisers.
Tip #6: Take a Soil Sample
If you’re not a professional gardener or landscaper, you may not think this matters. But soil samples show you the nutrient profile of your garden. This way, you can spot chemical deficiencies and buy the right lawn feed. Sampling will also show how much thatch, moss, mulch, or other materials are in the soil. You’ll see how loose or compacted it truly is.
Hollow tine hand-held corers are a good way to obtain soil samples but you can DIY. Use the lower section of the plug – the top will mostly be thatch. These samples will tell you what insects are in your soil, what nutrients you need to add, and even what type of soil you have (loam, clay, sand, mix). All this will guide you on how to choose the right lawn fertiliser.
Tip #7: Think About Application
How do you plan to feed your lawn? Whether organic (blood, feathers, bone, droppings) or synthetic (chemicals), you can apply your fertiliser as a spray or as broadcast granules. Dry fertiliser (granules) can be applied using a drop spreader or a rotary spreader. Rotary spreaders have a spinning disc fitted onto a knapsack, hand-crank, or wheeled wagon spreader.
You can apply liquid lawn feed by mixing it in a watering can and pouring directly onto your lawn. Or you can mix it in a container and transfer it to a knapsack sprayer with a hand pump. You can get over-the-counter pre-mixed liquid fertiliser in a spray bottle. This is best for small scale spot spraying. Or you can buy one that connects directly to your garden hose.
Tip #8: Consider the Location of your Lawn
This isn’t just about geographical information. We’re thinking about more practical factors. Is the lawn in your front garden or back yard? Does it flank any flowers or vegetables? Are there walkways through it or paving around it? These may not seem like key things but they are, and here’s why. If you have lots of pavers, a lot of fertiliser that falls on the concrete.
That’s waste. And if your lawn feed has ferrous supplements, they will stain your edging. So you need a drop spreader, top dressing, or side dressing to ensure all the lawn feed gets used up. You can also use fertiliser spikes and fertiliser sticks. These are convenient for hard-to-reach sections of your lawn. They’re good for spot treatment too … but only if you trust them.
Tip #9: Check the Time of Year
Not all of us are lawn professionals but a lot of us have lawns. And lawn feed manufacturers know that. So they stock supermarket shelves with user-friendly wysiwig spray bottles and dry bags. These lawn feed products are dumbed down to the max so that laymen can use them. Part of this tailoring is in the labels – you’ll see the lawn feed labelled by season.
Some lawn feed packs can be used at any time of year. Some cover a single season while some cut across two. So if you’re completely lost, get the Autumn Pack for October or the Summer Pack for July. As a general guide, mixed-release fertilisers are ideal and provides holistic results. They’ll give you both instant gratification and long-term lawn protection.
Tip #10: Consider the Seasons
This may sound the same as Tip #9 but there’s a slight difference. The previous point was about reading the product label. It’s the quickest way to pick the right fertiliser for your region and season. But this tip is about seasonal needs rather than seasonal brands. If your lawn is young and new, you want to focus on the phosphorous to be sure the lawn takes root.
In the spring, use a high-nitrate slow-release fertiliser to help the lawn up from hibernation. In the summer, slow-release organic fertilisers are best. They can withstand summer heat and are less likely to burn your grass. In autumn, pick a brand that’s rich in potassium. It’ll strengthen the stems and roots during winter dormancy. For winter, pre-emergents are best.
Tip #11: Size Up the Situation
The reason so many people rush for liquid lawn feed is convenience. Especially store-bought spray bottle fertilisers or hose-lined fertiliser. With these two types, all you do is spray. But mixing liquid concentrate is trickier. And faster. So if you’re greening up for an event, get some concentrate. It absorbs instantly and will show visible results within a few hours.
What about dry feed though? Granules often come in two sizes. Small granules (under 2mm) are barely visible so they’re best for subtle settings and high-traffic areas Because they have a lower surface area: volume ratio, they’re absorbed quicker. Large granules (2mm to 3mm) offer more psychological comfort because you can see them. They’re good for spot feeding.
Tip #12: Focus on Your End Goal
Why exactly are you applying lawn fertiliser? Are you reviving the garden after winter? Or repairing the neglected lawn after being away for the summer? Maybe you’ve spotted bald patches that need some TLC. Or you’ve noticed your grass is yellowing or purpling and you want it back to green? Or it could be that you’ve dethatched and de-mossed in recent times.
So now your lawn is dark and raw so it needs some first aid. Each of these scenarios calls for a different kind of fertiliser. Moss is killed off (or rather burnt) using iron and seaweed. The iron will green the grass, and nitrates will help as well. Buy a product seed and feed combo like Evergreen Miracle-Gro Lawn Repair Kit. The package mixes grass seeds and fertiliser.
Tip #13: Figure Out How Long You Need It
It’s unwise to feed your lawn amid heavy rains. This is because most of the lawn fertiliser will wash away unused. Worse, it may contaminate your veggie patch, orchard, flower bed, or the communal water supply. So you want to fertilise when the soil is damp but runoff is low. You can fertilise monthly or annually depending on the weather (and the state of your lawn).
Also, how much time can you set aside for yard work? If you’re really busy, buy a product with extra-long latency. These slow-release lawn feeds stay in the soil for up to six months. But if you fuss in the garden every week, get a short-span fertiliser that lasts three months. Longer lawn feed can be applied once or twice a year. Shorter ones can be repeated every few weeks.
Tip #14: Take a Hint
Sometimes, the type of weeds in your lawn can show you what’s missing. If you have excess moss, your soil is probably water-logged and needs aeration. Other weeds that beg for coring include creepers like mint, horsetail, and buttercup. Other weed roots can’t penetrate the compacted soil so these vines take over. But if your weeds are leguminous, it’s a nitrate thing.
Check for heavy clover cover, sandbur, or ivy. These imply your soil needs more nitrogen. Most lawns have a mix of grass varieties. Meaning the species you dislike are seen as weeds. So if you spot crabgrass or bluegrass, your lawn is high in magnesium, chlorine, and potassium but low in calcium and phosphorous. Buckhorn and burdock show low calcium.
Tip #15: Mix Your Macros and Your Micros
The primary ingredients of lawn fertilisers are nitrogen, phosphorous, and potassium – they’re macronutrients. Your lawn also needs micronutrients like iron, manganese, and magnesium. When using weeds as soil gauges, consider the underground elements.
Lawns rich in iron and sulphur may sprout burdock. Buckhorn and chickweed prefer sodium. Starter pack fertilisers are all about the phosphorous so the middle number in their NPK is probably the largest. Late spring fertilisers should focus on water retention and weed control, so nitrates work best. They’ll have a big number at the front to show high nitrogen.
Winter fertilisers are generally potassium-heavy so they’ll have a high 3rd number in their NPK ratio. Pick a product with the right NPK plus a good dose of micronutrients. You can even get feather food, blood meal and liquid seaweed! They’re all quirky, safe, and organic.
What kind of fertiliser have you put on your lawn? And did it work? Tell us in the comments!
