What to grow in your greenhouse in September

With summer now coming to an end, the nights are getting longer and the temperatures cooler, Autumn is on its way. September is the perfect month for gardeners, as harvesting is in full swing and preparation for spring can begin. So, whether you are looking for inspiration on what to plant in your greenhouse this September, or wondering what jobs you should be doing, keep reading, as we explore what you can do with your greenhouse throughout September.

What to grow

September is the perfect time to get ahead and start planting for next year. So, throughout September you can start planting your spring vegetables, such as your spring onions and garlic cloves, as well as some of your spring bulbs for the next season. But don’t worry, you can still plant crops such as turnips that can be enjoyed this year ready for an Autumn and Winter harvest.

Turnips

As fast-growing crops, turnips are a great plant to grow in September as they will be ready for harvest within as little as 6 weeks after planting, meaning you can enjoy fresh turnips by mid to late Autumn. Planting your turnips in your greenhouse, instead of directly in the ground, offers your turnips an added layer of protection from the unpredictable weather we often have in September. When planting your turnips ensure that you’re planting in a large container with good quality multi-purpose soil. Water your turnips regularly, and harvest when they are roughly the size of a golf-ball.

Spring onions

Spring onions are extremely low maintenance plants to grow and make great additions to our greenhouses in September. When planting spring onions in your greenhouse you can plant them in different ways depending on whether you will be planting out your spring onions.

If you are opting to start your spring onions in your greenhouse but are planning on transplanting them in the future, we recommend planting your spring onions in seed trays.

But if you are planning to grow your spring onions solely within your greenhouse, we recommend planting your spring onions directly into a pot or container. But whatever way you are choosing to grow your spring onions this September, we have created a guide on how to grow your spring onions to ensure they thrive.

Planting Spring Onions in Seed Trays

If you opt to plant your spring onions into seed trays, ensure that your trays have good draining holes, to minimise the risk of your soil becoming waterlogged through watering.  Before planting your spring onion, prepare your soil mixture of well-draining soil and fertiliser.

Once you have prepared your soil mix, ensure that the consistency is fine and fill your seed trays. When sowing your spring onions ensure that they are evenly distributed in your trays and cover with a fine layer of soil and water thoroughly. Once your spring onions have produced seedlings that are roughly 6 inches in height, you can transplant your seedlings outside to continue growing. 

Planting Spring Onions in Pots or Containers

Like planting in seed trays, you will need to ensure that your pot or container has sufficient draining holes prior to planting. Fill your pot or container with your soil mixture and finely sow your spring onion seeds evenly throughout your pot or container. Ensure that your pot or container is located in an area of your greenhouse that receives lots of natural light throughout the day.

Once you have sown your spring onion seeds, cover the seeds with a thin layer of soil, to promote germination and water thoroughly. Once your seeds have germinated, thin your seeds within the pot or container, with spacing of around 2 inches between your seeds. Ensure that you are regularly watering your spring onions and watch them grow.

Garlic Cloves

Garlic can be planted in your greenhouse between September to November, so September is the perfect time to make a start on planting your garlic for the spring.

Prior to planting your garlic, ensure that you prepare a large pot or container, with sufficient draining holes, with well-draining soil. After preparing your pot or container plant your garlic cloves into your soil at a depth of around 2-3 inches, ensuring that each clove is separated and planted individually, with spacing of around 6 inches between your cloves. When planting your garlic cloves, ensure that the rounded end of your clove is positioned at the bottom and the point of your clove is facing upwards.

After planting your garlic cloves, ensure that you water frequently keeping the soil moist, but not waterlogged as garlic is not a fan of overly moist soil conditions. Garlic is not a fast-growing plant, so your garlic will not be ready for harvesting until well into next year, but depending on the variety of garlic you grow, the time it takes your garlic cloves to mature can vary. At Rhino Greenhouses Direct we expect that garlic planted in September should be ready to harvest by June of the following year. A great tip to check if your garlic is ready for harvesting is to check the leaves on your garlic, if the leaves become soft and appear to wither, it's time to harvest! To harvest your garlic, gently dig up your garlic bulbs from the soil.

Wondering what to make with your garlic? Try some of these recipes below:

- Wild Garlic Polenta with Barbequed Asparagus
- Parsnip, Roast Garlic & Chesnut Soup

Spring Bulbs

Alongside planting crops in preparation for spring, your greenhouse is a great place to plant your spring bulbs in September. Bulbs such as Daffodils, Crocus and Hyacinths, can be planted in your greenhouse and later transplanted into the ground once established. Planting your spring bulbs in your greenhouse throughout September enables your bulbs to have an added layer of protection from the cold, as well as animals in your garden, enabling your bulbs the time to establish their roots prior to being moved to the ground. Your greenhouse not only protects your bulbs but has the perfect conditions for your spring bulbs to establish, as they need plenty of sunshine to thrive.

Rhino Greenhouses tips

September is the perfect time to give your greenhouse a much-needed tidy, after a busy summer of planting and harvesting. As the harvest period comes to an end, ensure that you are removing any dead or dying plants from your greenhouse. Keeping on top of your greenhouse in September will minimise the risk of pests and diseases spreading in your space.

Wondering what you could grow in your greenhouse over Autumn and Winter, check out our seasonal guide for what to grow in your greenhouse or follow the next in the series and check out what to grow in your greenhouse in October.

For more inspiration on what you could be growing in your greenhouse in September, check out our wonderful friend Ellen Mary’s latest September post.