Beginner’s Guide to Vegetable Gardening – Part 3, When to Sow Seeds and Plant Seedlings

vegetable seedlings in garden bed

Sowing Seeds and Planting Seedlings at The Right Time of the Year

Once you’ve selected a good location to start a food garden, and prepared the soil in the garden bed to make it suitable for growing plants, the next step is to plant it up!

Before any planting is done though, there are a few questions that we need to answer:

  • What vegetables and herbs do we wish to grow, and are they in season?
  • Should we plant seeds or seedlings?
  • How much produce would we like to harvest?
  • How often would we like to harvest our produce?

Remember, you can’t be prepared if you don’t plan! What you do now will determine how much food you’ll have at a future date, so it’s best to be systematic. Being impulsive and taking an ad-hoc approach with matters such as this will always lead to situations of being unprepared.

In this article we’ll look at everything that needs to be done to ensure that we get a consistent harvest month after month to meet our food needs.

Seedlings or Seeds, What’s the Difference, Which is Better?

punnet of cress seedlings
A punnet of cress seedlings

Growing vegetables from seedlings is much easier than growing from vegetables seed, because the initial work of sowing seeds and raising seedlings is already done for you.

If you’ve never done any food gardening before and don’t want to be needlessly discouraged at the outset, it’s best to begin with seedlings. A punnet of seedlings usually contains around 6-8 young plants.

The advantage of seeds is that they’re much cheaper, you get a lot of seeds in a packet, and they can be planted repeatedly throughout the growing season. Be aware that all seeds have a limited life, they don’t keep forever, so there’s no point hoarding them! For further information on how long different seeds can be kept, please see my article – Seed Saving – How Long Can You Keep Seeds?

Regardless of whether you choose seedlings or seeds to grow food, there are some rules of nature which all of humanity has been forced to follow since the advent of agriculture 10,000 years ago, and these rules are dictated by the seasons of the planet we all know well, spring, summer, autumn and winter, together with climate.

Nature decides when certain vegetables are planted, and when they can’t be planted, and there’s nothing much we can do about that.

We can artificially extend the productive season by growing warm season plants in greenhouses, which allow us to start warm season vegetables a bit earlier and keep them producing further into the season when the weather begins to cools down. Large greenhouses can get expensive, and artificially heated greenhouses are out of the reach of most people in terms of purchase and running costs!

What this means is we have to grow plants when they’re in season! How do we know what to grow when? We use a garden calendar.

Know What to Plant When, Using a Garden Calendar

seed sowing garden calendar
A sample section of a gardening calendar

Ready to plant seeds or seedlings?

  • It’s important to plant seedlings or sow seeds in the correct season, as some plants such as tomatoes, eggplants, cucumbers and chillies grow in the warmer seasons (spring-summer), while others such as cabbage, cauliflower, and broccoli grow in the cooler seasons (autumn-winter), while a few, like lettuce can grow almost all year.
  • You can’t just plant at any time during the correct season though, you must also plant seedlings or sow seeds in the correct months of their season.
  • You can plant seedlings or sow seeds every month, all year round, but the types of vegetables and herbs you can plant changes from month to month, which is why there’s a gardening calendar for each and every month of the year.

To know which vegetables and herbs are in season, and when they should be planted, gardeners use a gardening calendar.

You will need a gardening calendar for your location, different climates (cool, temperate, subtropical, tropical and arid) affect the planting times and what can be grown.

Gardening calendars are based around the monthly cycle, and a good gardening calendar will tell you:

  • what weather to expect for that month
  • gardening tasks that need to be carried out during that month
  • what seeds to sow, where to sow them (in the ground in in a seed tray) and how many weeks till harvest

Where Can I Get a Free Gardening Calendar?

  1. Check with your local gardening groups, community gardens or local government, many have free gardening calendars.
  2. Online gardening calendars are great as long as you select the correct climate zone for your location, ! recommend the website Gardenate, its very good, and also lets you search by food plants to see which months they can be sown as a seed or planted as a seedling.
  3. I produce a free gardening calendar for Melbourne Australia, which is where I’m based. I’m in a temperate climate, and some US readers who live in similar climates use my calendar and ‘flip=over’ the months so it makes sense.

Converting months to seasons for different hemispheres

If you’re a gardener from the Southern hemisphere (such as Australia, New Zealand) reading gardening material from the Northern hemisphere (US, UK, Canada) and need to convert seasons to months, I’ve created the seasonal conversion table shown below to make the task easier.

season timing conversion chart
Season conversion chart for northern and southern hemisphere seasons

Note: click on graphic above to enlarge and save image, or download the PDF version of the gardening season timing and conversion chart for printing

Want to learn more about the various categories of seasons and how the seasons come about, see my article  – Converting Months to Seasons – Northern and Southern Hemisphere, Meteorological and Astronomical

How to Use a Gardening Calendar for Seedlings Rather Than Seeds

Gardening calendars are typically seed sowing calendars. What if you’re planting seedlings?

Seedlings are usually 4-6 weeks ahead of seeds, which simply means that if you plant a seed, it takes 4-6 weeks to grow into a decent seedling

So when you buy seedlings to plant, and want to know what’s in season, refer to the previous month’s calendar, because that’s when these plants were seeds!

Ethical garden nurseries will only sell seeds and seedlings when they are in season, and take them off the shelves when they’re not, the big chain stores usually don’t do that so keep this in mind.

Once we’ve selected the appropriate seeds or seedlings that are in season, it’s planting time!

Sowing Seeds and Planting Seedlings, How Much and How Often?

field of lettuce
How much lettuce do you need all at once? (Image credits – Wikipedia commons Rodney Burton / Lettuce harvest, Methwold Common, Norfolk / CC BY-SA 2.0)

Many new gardeners buy a packet of seeds and plant the lot all at once, never do that!

If you do that with lettuce seeds, of which there are a few hundred in a pack, you’ll end up with at least 100 lettuce plants after 8-12 weeks (2-3 months), and they’ll all be ready to harvest around the same time, but they only keep for a week in the vegetable crisper drawer of the refrigerator.

Similarly, you’d never go to the supermarket and purchase a dozen heads of cabbage all at once, so it makes no sense to plant that many all at once, because that’s what will happen after 8-15 weeks.

With a pack of seeds you decide how many you will sow, but with a punnet of seedlings usually contains around 6-9 plants, what happens of you buy one and don’t need to use all the plants all at once?

It is possible to only use part of the punnet to buy some time, and plant the rest a fortnight later. The other option is to give the spare plants to friends, or to swap their surplus seedlings with them. This is a real community-building gesture which fosters generosity and a culture of helping each other out. This is how resilient communities function.

Planning Seed Sowing and Seedling Planting to Meet Your Food Needs

There’s a sensible way to sow seeds and plant seedlings which makes best use of available garden space and minimises food waste:

  • Only put in as much plants (seeds or seedlings) every two weeks as you would buy from a greengrocer or supermarket every two weeks!
  • Put a mix of plants into the garden, ones with short harvest periods, medium harvest periods, and long harvest periods to keep the supply of food constant.

If you use ten lettuce plants each fortnight (2-week period), then plants a bit more than ten lettuce plants each fortnight, it’s that simple.

Using this method with the various vegetables that are in season, you’ll have a garden in which there will be something to harvest each and every week, and there will be space to plant more each fortnight.

It’s a good idea to plant a bit extra than you might use, just in case any plants die for any reason or get eaten by pests. Any excess may be able to be preserved, or swapped within the community for other food you may not have grown yourself.

If we look at any gardening calendar, we see that the time to harvest is listed. This is how many weeks it will take from when we sow the seeds to when the plants are ready to be harvested.

With seedlings, the time-to-harvest is 4-6 weeks less than seeds because they’ve already had 4-6 weeks of growing time when they’re purchased. Many seedling labels give an estimate of time-to-harvest, along with plant spacing and sun requirements.

Planting a Diverse Food Garden for Increased Resilience and Continuous Cropping

Looking at the gardening calendar for any month, we see that some plants can be harvested very quickly, radishes are ready to eat in 5-7 weeks, which is a bit more than a month, while garlic takes 17-25 weeks, which is almost half a year!

If you fill the garden with short harvest time plants, you’ll be forever harvesting and replanting, but conversely, a garden filled with long harvest period plants will have you waiting for ages while the garden produces nothing at all. By growing various vegetables in the garden, there is always something to pick on any day, and the garden is far more resilient. You’re not placing all your eggs in one basket so to speak. If there’s a bad season and one vegetable crop fails, there will be plenty more to carry you through.

By having a range of food crops to rely on each season, we eliminate any single point of failure in a garden. This approach to creating resilient food production systems can also be used for fruit tree orchards and any other productive crops, and is described in the permaculture design (ecological gardening design) principle ‘Each Important Function is Supported by Many Elements’.

So, to summarise, for successful food gardening, the goal is not to fill all available space all at once, but to plant a variety of crops at the same rate that you would harvest them, allowing for some surplus as a bit of insurance against mishaps. This approach will provide continuous cropping, and a regular supply of produce to the kitchen table!

Once we know what seeds we’ll be planting, how many, and how often, the next step is to sow the seeds, as discussed in the next article  – Part 4, How to Sow Seeds Directly Into the Ground and Into Seedling Trays.

2 thoughts on “Beginner’s Guide to Vegetable Gardening – Part 3, When to Sow Seeds and Plant Seedlings

    1. Thanks Mike, I started organic gardening in 2002, and studies permaculture in 2008. I’ve been working professionally as a horticulturist and formally employed to teach sustainable gardening since 2012. It’s what I do! 🙂

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