Why Summer Lawn Fertilising Matters
The summer months present unique challenges for your lawn. Intense sun, potential heatwaves, and increased foot traffic can all stress grass, making it more susceptible to disease and browning. While it might seem counterintuitive to feed a lawn under such conditions, judicious lawn fertilising in summer can actually bolster its resilience and maintain its appearance. The right fertiliser provides essential nutrients that help the grass recover from stress, retain moisture, and continue healthy growth, albeit at a slower pace during peak heat.
Choosing when and how to fertilise during summer is key. Unlike spring or autumn applications, summer feeding often requires lighter, more frequent applications of specific nutrient blends to avoid scorching the grass or encouraging excessive top growth that can't be supported by the roots in hot weather. The goal is to maintain health and colour without pushing the lawn beyond its capabilities.
It's important to differentiate summer lawn fertiliser from other seasons. Spring feeding typically focuses on recovery and new growth, while autumn applications prepare the lawn for winter dormancy. Summer feeding, however, is about sustenance and stress management. It aims to keep the grass green and healthy through the harshest growing period, ensuring it can withstand the heat and drought that often characterise the season.
- Summer fertilising helps lawns cope with heat and drought stress.
- Judicious application maintains health and colour through hot weather.
- Tailor summer feeds to nutrient needs and avoid encouraging weak growth.
When considering lawn fertilising in summer, think about the grass's metabolic rate. During extreme heat, growth slows. Pushing it too hard with high-nitrogen fertilisers can lead to weak, leggy growth that wilts quickly and is prone to fungal infections. This is why a balanced approach, often favouring potassium for drought tolerance, is frequently recommended.
Choosing the Right Lawn Feed for Summer
Selecting the appropriate fertiliser is paramount when undertaking lawn fertilising in summer. The composition of the feed, particularly the nitrogen (N), phosphorus (P), and potassium (K) ratio, needs careful consideration. High nitrogen levels, common in spring feeds, can stimulate rapid leafy growth that is easily scorched by the sun and can also lead to disease if not managed carefully. Instead, opt for fertilisers with a balanced nutrient profile or those specifically formulated for summer use.
Understanding Nutrient Ratios (NPK)
For summer, a fertiliser with a lower nitrogen content and a higher proportion of potassium (K) is often beneficial. Potassium strengthens cell walls, enhancing the lawn's ability to withstand drought, heat stress, and disease. A feed like a 10-0-10 or a similar ratio, providing balanced nitrogen for colour and sufficient potassium for resilience, is a common recommendation. Some specialised summer feeds might also include slow-release nitrogen to provide a steady supply of nutrients without a sudden growth surge.
Types of Fertilisers Available
You'll encounter several types of lawn fertilisers. Granular feeds are popular for their ease of application and the option of slow-release formulations, which gradually release nutrients over several weeks. Liquid feeds offer a quicker green-up but require more frequent application and careful measurement to avoid burning the lawn. Organic fertilisers, such as pelleted chicken manure or seaweed extracts, provide nutrients gradually and also help improve soil health, making them a gentler option for summer feeding.
Apply fertiliser just before a natural rainfall if possible, or water it in thoroughly immediately after application. This helps the nutrients dissolve and be absorbed by the soil, reducing the risk of leaf scorch and ensuring the feed reaches the roots.
When to Avoid Fertilising
There are times when applying fertiliser is best avoided. If your lawn is already suffering from severe drought stress, appearing brown and dry, applying fertiliser can exacerbate the problem. Wait until conditions improve, perhaps with natural rainfall or after you've initiated a consistent watering schedule. Similarly, if you've recently scarified or aerated the lawn, it's generally advisable to wait a week or two before fertilising to allow the grass to recover from the mechanical stress.
It's better to underfeed your lawn in summer than to overfeed it and risk damage.
The decision to fertilise your lawn in summer also depends on its current condition and the weather forecast. If your lawn is already lush and green and no drought is predicted, you might be able to skip a summer feed altogether or opt for a very light application. Always check the weather; extreme heatwaves might be a signal to hold off until temperatures moderate.
Application Techniques for Summer Fertilising
The method of application is as critical as the product itself when it comes to lawn fertilising in summer. Incorrect application can lead to uneven growth, yellow patches, or, in the worst-case scenario, severe burning of the grass blades. Adhering to recommended dosages and ensuring even distribution are paramount to achieving the desired results without damaging your lawn.
Using a Lawn Spreader
For granular fertilisers, a spreader is an invaluable tool. Rotary spreaders distribute granules in a wide arc, while drop spreaders apply them in a more targeted, narrower band. Whichever type you use, ensure it is calibrated correctly according to the fertiliser manufacturer's instructions. Apply in parallel lines, overlapping slightly to avoid striping and ensuring complete coverage. If applying across the width, turn the spreader off before reaching the edge to prevent excess product from falling onto flowerbeds or pathways.
Watering In
This is perhaps the most crucial step after applying fertiliser. If the weather is dry, you must water the lawn thoroughly with at least 10-15mm of water soon after application. This helps the fertiliser granules dissolve and move into the soil, where the roots can access them. If fertiliser granules are left sitting on the grass blades, especially during hot, sunny weather, they can cause significant yellowing and browning, commonly known as fertiliser scorch. Always consult the product packaging for specific watering-in instructions.
Always read and follow the specific application instructions provided on the fertiliser packaging.
How Much to Apply
Over-application is a common mistake, particularly during summer. It's crucial to stick to the recommended rate on the product label. If you're concerned about the heat, consider applying at a slightly reduced rate, especially if using a high-nitrogen product. Many gardeners opt for lighter, more frequent applications during summer rather than a single heavy dose. For example, instead of one large application of a feed designed to last 8-10 weeks, you might use a milder feed every 4-6 weeks.
Timing Your Application
The best time of day for lawn fertilising in summer is typically in the early morning or late evening when temperatures are cooler and the sun is less intense. This minimises the risk of scorching and allows the grass to absorb the nutrients without immediate heat stress. Avoid applying fertiliser during the hottest part of the day. If you are using a liquid feed, ensure you follow the manufacturer's instructions regarding when to apply it relative to mowing, as some require the grass to be dry, while others can be applied to damp grass.
Common Pitfalls and Alternatives in Summer Lawn Care
While focusing on lawn fertilising in summer, it's important to be aware of common mistakes that can undo your efforts. Over-fertilising, applying at the wrong time of day, or using inappropriate products are frequent culprits. Understanding these pitfalls helps ensure your lawn remains healthy and resilient throughout the warmer months. Beyond fertilising, other aspects of lawn maintenance are equally vital during summer.
Avoiding Fertiliser Burn
As mentioned, fertiliser burn is a primary concern. This occurs when the salts in the fertiliser draw moisture out of the grass blades, causing them to dry out and turn brown. It's often a result of over-application, not watering the fertiliser in, or applying it during extreme heat. If you spot burn, water the affected area heavily to try and dilute the fertiliser and rehydrate the grass. It may recover, but it takes time.
Mowing Practices
During summer, it's often advised to slightly raise your mower's cutting height. Taller grass blades shade the soil, helping to retain moisture and keep the soil cooler, which reduces stress on the roots. Avoid mowing when the grass is dry and brittle, or when the ground is excessively dry. If you have a very fine lawn, you might need to adjust your mowing frequency to avoid removing more than one-third of the grass blade length at any single mowing session.
Consider a slow-release fertiliser or an organic option for summer to provide a consistent, gentle feed that is less likely to burn the lawn compared to quick-release synthetics.
Watering Strategies
Deep, infrequent watering is generally more effective than light, frequent watering. Aim to water thoroughly to encourage roots to grow deeper into the soil, making the lawn more drought-tolerant. Water early in the morning to minimise evaporation and allow the grass to dry before nightfall, reducing the risk of fungal diseases. If you notice signs of stress, such as wilting or a bluish-grey tint, it's time to water.
Alternative Approaches
Not everyone needs or wants to use chemical fertilisers. For a more natural approach, consider using compost tea or seaweed extracts, which provide nutrients and also beneficial microbes. Some gardeners also opt for 'feed and seed' products, which can help fill in any thin patches and provide nutrients simultaneously, though careful timing is needed to ensure the seed germinates successfully without being stressed by heat or existing lawn growth.
Maintaining a healthy soil microbiome can make your lawn more resilient to summer stresses, reducing the need for heavy fertilisation.
For lawns that are persistently struggling, consider professional advice or more in-depth soil analysis. Sometimes, underlying issues like poor drainage, compacted soil, or pest infestations might be the root cause of poor lawn health, and fertilising alone won't solve them. Addressing these foundational issues is often a more sustainable long-term strategy than relying solely on summer lawn fertilising.