September is a crucial month for any gardening enthusiast, especially in Mediterranean climates. With the end of summer and the gradual arrival of autumn, it is the ideal time to prepare the garden, terrace or vegetable patch for the new season. What should you plant in September? How should you care for plants after the summer heat? Which tasks are essential this month? In this article, you’ll find a practical guide with all the gardening tips for September: from pruning and watering to which flowers and vegetables to sow to ensure a healthy, beautiful and productive green space.
Whether you're a beginner or have experience, here you'll find everything you need to know to care for your garden in September.
1. How should you fertilise the garden in September?
With the arrival of the first cool nights, it is essential to strengthen your plants with the right nutrients. Good fertilising at this time of year helps not only to keep the garden healthy after summer, but also to prepare it for autumn and winter. Here are some key points to choose the most suitable fertiliser depending on the type of plant and its needs:
Slow-release fertilisers: They are your ideal allies in September. They provide nutrients gradually over weeks, allowing for consistent feeding without the need to fertilise frequently.
Potassium-rich fertilisers: This nutrient is key to strengthening roots and improving plants' resistance to disease and low temperatures. They are especially useful if you want your garden to go into winter strong.
Balanced fertilisers for potted plants: Pots have a limited volume of soil, and their nutrients are used up more quickly. Replenishing them with a balanced fertiliser ensures healthy, vigorous growth.
Special fertiliser for fruit trees and citrus plants: After the effort of fruiting, trees need an extra boost to recover their strength. A fertiliser formulated especially for them will give them exactly what they need.
Homemade compost: If you have compost made at home, use it! It is a natural and sustainable way to improve soil structure, increase water retention and add organic matter.
Extra tip: It is always better to fertilise in the morning or at the end of the day, avoiding the hottest hours. And remember to water well after fertilising to help the nutrients be absorbed.
2. What to plant in September?
September is one of the best months of the year to renew and enrich your garden. Temperatures begin to soften, the soil still holds the summer heat and autumn rains help new plants take root. It is the ideal time to think ahead, and prepare the garden so it looks spectacular in spring.
Here are some ideas to make the most of this planting season:
Seasonal flowering plants Bring instant colour to your garden with flowers such as chrysanthemums, pansies or asters. They are resilient to temperature changes and offer a burst of colour just when many other plants begin to fade.
Trees and shrubs Planting in September allows trees and shrubs to develop a strong root system during autumn and winter. It is the perfect time to introduce Mediterranean species such as strawberry tree, carob tree or bay laurel, which also require little maintenance.
Hardy climbers If you're thinking of adding height or covering walls and pergolas, this is the time to plant climbers such as bougainvillea, honeysuckle or passionflower. They bring vertical interest and structure to the garden, and will bloom strongly next season.
Spring bulbs Don't forget the classics like tulips, daffodils or hyacinths. Although their flowers won't appear until March or April, they need to be planted now so they can spend the winter underground and bloom in full.
Ground-cover and spreading plants If you want to cover bare ground or control erosion on slopes, take the opportunity to plant species such as vinca, thyme or dichondra, which adapt well to the Mediterranean climate.
Eiviss Garden tip: Before planting, check the condition of the growing medium and consider adding compost or organic matter to improve the soil structure. That way, your new plants will get off to a strong and healthy start.
3. Indoor plants
As the start of a new season arrives, it's not just your outdoor garden that notices: indoor plants feel the change too. As the days get shorter and temperatures drop, it's essential to adapt their care so they stay healthy and beautiful throughout autumn and winter.
Here are some key tips to pamper your indoor plants this month:
Natural light: a key factor With fewer hours of sunlight, many plants can struggle if they don't receive enough light. Move them closer to windows, preferably south- or west-facing, and remember to rotate the pots each week so they grow evenly. If you live in an area with little natural light, consider adding a grow light.
Water more sparingly: water needs decrease as temperatures fall and the plant enters a slower growth stage. Water only when the growing medium feels dry to the touch, avoiding excess moisture that could cause fungus or root rot.
Temperature and placement: September is a good time to think about where your plants will spend the winter. Look for warm spaces away from draughts or direct heat sources such as radiators. Constant temperatures between 18ºC and 22ºC are usually ideal for most indoor species.
Cleaning and plant health: take the opportunity to clean the leaves with a damp cloth and remove dust that could hinder photosynthesis. It is also a good time to check for pests such as mealybugs or mites, which are more common when the seasons change.
Final light feeding: you can apply a gentle fertiliser at the beginning of the month, before stopping feeding in autumn. This will give your plants a little boost before they enter their resting phase.
4. Kitchen garden
September is a month of abundance and preparation in the kitchen garden:
Harvest time! September is synonymous with abundance. Harvest ripe tomatoes, peppers, courgettes, aubergines, cucumbers and fragrant herbs such as basil or parsley. The more you pick, the more energy the plant can devote to producing new fruit before the season ends.
Autumn sowing: start planning your next harvest. Even when summer ends, your kitchen garden can keep producing. It’s the ideal time to sow long-cycle vegetables that will grow as temperatures begin to drop. Some good options to plant in September are:
Broccoli
Cabbages (white cabbage, red cabbage, kale)
Spinach
Chard
Winter lettuces
Radishes
Prepare the soil: aerate the earth, remove the remains of spent crops and enrich the soil with compost or organic fertilisers. This will help maintain soil fertility and reduce the risk of disease in new crops.
Watering adjusted to the weather: with temperatures falling and the possibility of some rain, it’s advisable to reduce watering frequency. Make sure the growing medium is not constantly damp to avoid fungal growth.
Pest and disease control: the end of summer can also bring unwanted visitors to the kitchen garden. Check the leaves for signs of aphids, caterpillars or fungi, and use eco-friendly control methods if necessary.
Eiviss Garden tip: September is also a good time to install protective structures such as mini-greenhouses, shade nets or tunnels to extend the growing season and protect your more delicate plants.
5. Lawn
The lawn also needs special attention during this transitional month:
Proper watering: Reduce watering frequency, taking advantage of cooler temperatures to maximise absorption.
Regular mowing: Keep the lawn mown, but not too short, to avoid stress and susceptibility to disease.
Aeration: Use an aerator to improve the penetration of water, air and nutrients into the soil.
Fertilisation: Apply a slow-release fertiliser to strengthen the roots before winter.
Weed control and repair: Remove weeds and repair damaged areas for a healthy lawn next season.
With these gardening tips, you will not only ensure a healthy, beautiful garden, but also a space of peace and tranquillity. Every effort in the garden brings great rewards, so keep nurturing your passion for gardening!
Share your experiences! How do you prepare your garden in September? Let us know in the comments and share this article with your plant-loving friends. If you need help, the Eiviss Garden team is always available to assist you.
