Sowing seeds outdoors is a cheap, fun and easy way to start a vegetable garden, and the heat of spring and summer helps to create the perfect environment for many of our favourite crops. While many vegetables can be given a good head start by sowing indoors, on windowsills, or sowing in greenhouses, there are some plants that prefer to be sown directly out into the garden.
In this article, we’ll explore what plants to sow outdoors, when to sow them, and how to create the right soil for sowing outdoors. Our guide includes step-by-step instructions on how to sow in drills, how to sow without drills, and how to sow in containers outdoors.
Sowing seeds outdoors
The benefits of sowing seeds outdoors include:
- Money-saving
- Space-saving
- Time-saving
- Crop strength
- Staggering your crops for a longer harvest
It’s easy to assume that plants grow the same way wherever they are planted, but most plants and vegetables adapt to their conditions. By sowing seeds outdoors you can not only save yourself time and money but create stronger crops.
Seeds started outdoors develop stronger roots and have a better relationship with bacteria and beneficial funguses in the soil. By sowing seeds indoors, and later transplanting them, many plants suffer from shock when they are moved.
This isn’t always the case though, and as we’ll talk about later, some seeds really are better sown indoors!
How do you sow seeds outside?
There are a few different ways to sow seeds outside, but all are pretty straightforward. The key to direct sowing seeds is soil. If you get your soil right, your seeds will germinate faster and develop stronger roots.
How to prepare your soil
Before you follow any of the guides to sowing in drills, sowing without drills or sowing seeds in containers, you need to prepare your soil.
Most vegetable seeds need well-drained, nutrient-rich compost mixed with standard weed-free garden soil. The easiest way to prepare beds for sowing seeds is to create a no-dig bed:
- Start by removing the worst of the weeds, either weeding with a hoe or just weeding by hand.
- Build raised sides out of treated timber or any materials that won’t rot (15cm / 0.5ft will stop most weeds).
- Lay newspaper or cardboard over the soil to stop light and create an organic and permeable weed barrier that allows drainage.
- Add a 50:50 mix of garden compost and weed-free soil over the top to fill the bed.
- Rake smooth and break up any large clumps of soil.
Tip: If you don’t want to create a raised bed, simply remove any weeds, and cultivate the ground down to about 15cm deep to aerate compacted soil, mix in plenty of compost and then rake smooth.
How to sow in drills
Once you’ve prepared your soil, you’re ready to sow seeds outdoors. One easy way to keep track of your seeds is to sow in drills. Drills are straight, shallow trenches used to sow seeds that need burying; root crops like beetroot, radish, or potato tubers; or pulses like beans and peas).
Step by step guide
- Rake your bed until you have an even, level, surface.
- Create a 5cm deep trench by digging soil and mounding it next to the trench.
- Mark each end of the trench.
- Sow seeds thinly (for most vegetables, this means 5cm apart).
- Water the drills
- When germination begins, thin seedling out to the recommended spacing (enough space for the final plant to grow without competition – usually 1ft.)
- Use a garden hoe to remove any weeds between the rows through the season.
Tip: The best tool to create trenches is a hoe, and it allows you to dig without standing on the soil, but if you don’t have one, lay some timber across the soil so you don’t compact the earth.
How to sow without drills
Some vegetables like to be sown directly outdoors on the surface of the soil. This provides them with maximum light, and their roots search down below for water as they grow. Carrots and leaf crops like salads, spinach or mustard are much better sown without drills.
Step by step guide
- Remove all weeds and rake the earth.
- Mark rows using string so you can keep track of your seedlings.
- Sow seeds as thinly as possible along each row.
- Water each row well.
- Keep the soil evenly moist for 2-3 weeks until you see signs of germination.
Tip: It can help to soak the soil a day before sowing outdoors in summer to help loosen the structure and revive dry compost.
How to seeds in containers outdoors
For gardeners with small spaces (or big gardens that have run out of space) growing vegetable containers is easy. Sowing in containers is great for carrots that need deep soil, but also for salads and cabbage crops which benefit from being raised above slug level!
Fill a container with compost and sow directly on the surface. Cover seeds with a thin layer of soil to stop birds from getting them, then keep pots moist until you see germination.
Caring for direct-sown crops
How long do seeds take to germinate outside?
All plants, including vegetables, take different amounts of time to germinate. Some crops are biennial, while others are annual and there are some incredible perennial crops you can grow in your garden too.
- Annual: Grows from seed to harvest in a single year. Plants won’t return.
- Biennial: Develops roots and foliage in its first year, followed by fruits, flowers, or builds in its second year.
- Perennial: Grows well in its first year, and repeat flowers each year with no need to sow again.
Annual seeds usually germinate fastest and are best sown in spring. Annual vegetables like tomatoes, cucumbers, spring onions or radishes typically germinate in 7-14 days, but some take longer.
For example, carrot seeds have very erratic germination rates because their seeds have developed to last through cold temperatures. These ‘hardy annuals’ germinate when they are ready, so just be patient.
How to look after your seedlings
Once you’ve sown seeds outdoors, you need to give them the right amount of water, but just like indoor seedlings, they have small root systems and can’t cope with very damp soil.
Many gardeners will be familiar with the mantra “only water when the surface of the soil is dry” which works as a good rule of thumb for general plant care. However, for seedlings, keeping even soil moisture is important. Seedlings like consistency, so low levels of consistent moisture are much better for them than letting them dry, then soak, then dry, then soak, etc.
Keeping pests off seeds
The hardest part of caring for seedlings outdoors is keeping pests off them. Slugs and aphids are particularly problematic on young brassicas and beans, particularly in early spring when they are the first young shoots to appear.
Slugs will go to great lengths, traveling over copper, glass, wool, and even crawling through water, to reach tender seedlings. There are thousands of tips and tricks online for keeping slugs off seedlings but there are only two methods that we find genuinely work.
Two slug prevention methods that genuinely work are
- Eggshells
- Marigolds
Even our prized Hostas haven’t been touched by slugs this year thanks to eggshells, and last year we successfully grew an entire bed of slug-free cabbages thanks to a hedge of marigolds around the edge. Slugs might love seedlings, but if there’s one thing they love more it’s an easy meal.
Planting alternative (sacrificial) plants between slugs and your crops will almost always beat these lazy pests.
The Best Crops to Sow Outdoors
When to sow seeds outside
Deciding when to sow seeds outdoors depends on the vegetables you are growing. There are so many plants that can be happily planted outdoors from early spring to late fall.
- Salad crops can be sown at the very start of spring right through the mid-fall if you choose the right varieties and give them as much sunlight as possible.
- Spinach is a great crop to sow early. They can tolerate the fluctuating spring temperatures and like long growing seasons but are equally happy growing as leaf crops with sowing late into august.
- Broad beans are great for early sowing, and can even be sown in September for an early harvest in spring.
- Spring onions and salad onions grow quickly and can be direct sown almost all year round as long as the soil isn’t frozen. Give spring onions as much light as possible whenever you sow them and avoid waterlogging the soil.
We’ve published some great guides on what to sow in April and cool weather crops to help you make the most of your garden in the most difficult months, but wanted to put together a guide to help you plan your garden for the year ahead.
What to sow outdoors, and when to sow it:
Early spring | Late spring | Early summer | Late summer |
Artichoke Broad beans Beetroot Peas Broccoli Sprouts Cabbage Carrot Kale Spinach Rocket Kohlrabi Leek Lettuce Spring Onions Turnips | Artichoke Broad beans Beetroot Peas Broccoli Sprouts Cabbage Carrot Kale Spinach Rocket Kohlrabi Leek Lettuce Spring Onions Turnips Chard Marrows Sugar beet Runner beans French beans Dwarf beans Courgette | Courgette Pak Choi Sweetcorn Broad beans Beetroot Peas Cabbage Carrot Spinach Rocket Kohlrabi Leek Lettuce Spring Onions Chard Sugar beet Runner beans French beans Dwarf beans Courgette | Pak Choi Broad beans Peas Carrot Spinach Rocket Kohlrabi Lettuce Spring Onions Chard French beans Dwarf beans Courgette Pumpkins Squash Swede Spring greens Chinese cabbage |
Early fall | Late fall | Early winter | Late winter |
Cabbage Chinese cabbage Spring greens Lettuce Pak choi Radish Rocket Spinach Spring onion Kale | Broad beans Peas Leek | Broad beans Peas | Broad beans Peas Carrot Parsnip Radish |
Sowing seeds too early
But, what happens if you direct sow too early? Well, many plants are happy to sit in the soil until the time is right, like carrots, which are annual plants with germination triggered by temperature and day length. Carrot seeds can last in the soil right through winter and sprout in spring, so there is very little risk of sowing them too early.
Some plants don’t like being sown outside too early though. They include
- Radish
- Strawberries
- Leeks
- Onions
- Kale
- Beetroot
While it is possible to sow all of the above indoors, or even outdoors almost all year round, the results will be weak plants, with leggy seedlings that damp off or are eaten by slugs.
Beetroot, radish and leeks should only be sown directly outdoors in late spring when the weather starts to be drier, giving you more control over watering. Sowing these root and bulb crops outdoors too early in spring can often cause them to damp off in heavy rain, or just be pulled out by hungry birds that mistake them for worms.
Strawberries, kale and cabbages can be sown outdoors directly into the soil but don’t regulate their light levels well, so seeds tend to germinate as soon as they hit the soil. This means that they don’t have enough light to grow properly and are usually slow to develop making them incredibly vulnerable to pests.
Conclusion
Whatever the weather, there is always something you can sow outdoors in most climates, and in many cases, you will get much better crops as a result of sowing outdoors.
And don’t stop there, check out our seed sowing hacks to help make the most of your space with small seeds, and consider some of the companion plants, like chamomile, that you can sow alongside vegetables outdoors too.