Written by Rhi More
Starting seeds indoors allows you to get a jump start gardening before the last frost date has passed. You can direct seed in your garden if you prefer, but you will be harvesting veggies much sooner if you start your seeds indoors earlier in the spring. It’s always an option to buy transplants, but if you have the time, starting your plants from seed can be a really fun and gratifying process. Plus, you have many more options for trying out different varieties!
When to Start
To know when to start your seeds, the seed package is your best friend! There is usually lots of good growing info on packages including when to seed. When to start depends on the type of vegetable and the variety. For most crops you count back from the last expected frost date in order to determine when to seed. For example, tomatoes should be started 6-8 weeks before so count back from the last frost date for your area and start the seeds then. If you seed them earlier you will likely end up with stretched and overgrown tomato seedlings (see tip below if this is your case). To simplify things, one idea is to choose veggies that have similar growing needs and a similar growing timeline (for example, tomatoes and basil which we will focus on below).
What to Start
Some examples of heat loving crops to start indoors are tomatoes, peppers, eggplant, and basil. You can start cucumber and zucchini but beware that they don’t like to be transplanted – it’s a good idea to seed more than you need just in case!
You can also start cool weather crops inside like kale and brussel sprouts. You don’t have to wait for the chance of frost to be passed to plant these in the garden, but you also don’t want to plant them outside too early because a hard frost will kill the young plants (different story if you have a protected growing space or are well equipped to cover them). If you start them inside and then transplant the seedlings later in the spring, they will have a much better chance of surviving (and cover them up if temperatures dip below -8°C later in spring).
Tomato seeds should be started 6-8 weeks before the last frost date. For Halifax mid April is an excellent time to start tomatoes inside. It’s great to grow under lights, but don’t worry, having an indoor lighting setup isn’t completely necessary for growing tomatoes. Plants can be grown in a sunny, south facing window. Start seeds in small plug trays about ¼’’ deep and gently tamp down the soil – you want to make sure there is contact with the seed and soil for germination.
All seeds have different germination rates that will be listed on the package. Tomatoes take 5-6 days to germinate at a soil temperature of 80°C. Without heat they will likely take longer. It’s important to keep the soil moist during this period but not to water log it either because the seeds can rot (see below for how to bottom water). If you put a plastic dome over the tray the soil will stay moist and you will likely not need to water until after the seeds germinate. Tomato seeds don’t need light to germinate but if your house is on the colder side then keeping them in the sun may help the soil to stay warm and speed up germination. Once you see sprouts coming out of the soil make sure they have as much light as possible (minimum 8 hours but preferably 12-18 hours per day) and take off the plastic dome.
Potting up is a common term for transplanting seedlings into a larger pot size. For tomatoes, the more times you transplant the stronger the seedling will be, and it will help avoid them from getting leggy/stretched (when they outgrow their space and stretch when reaching for more light). When you pot up tomatoes, plant the seedling so deep that the soil is right below the first set of true leaves (the first set of leaves that appear are called the cotyledons and are not ‘true leaves’. Planting this deep allows roots to grow from the stem and will result in a stronger seedling. Imagine that you’re planting the tomato right up to it’s armpits. Also imagine if you didn’t plant the seedling deep like this – it would get very tall and spindly and have to be staked even before going in the garden!
Be careful not to over handle delicate tomato seedling stems when working with them – it’s best to gently pick them up by the leaves. If you start the seeds at the recommended time, after “potting up” a few times, you can pot them up to 6“ pots and end up with nice, big seedlings by the time the chance of frost has passed. Buying pots is not always necessary. Be creative and see what can be used around the house. Bottoms of 2 litre milk cartons with holes poked in the bottom can make excellent pots!
You can simply use a watering can to water your seedlings, but they do benefit from bottom watering. Make sure you have a tray with no holes underneath your plug trays or pots. Fill that tray about ¼ full of water. Wait for about 20-30 minutes then dump out any water remaining in the tray. This method of watering will allow the soil to uptake the amount of water it needs and will help avoid root rot and fungus. When the soil looks dry, always check about ½ an inch below the surface to make sure it isn’t already moist underneath. Bottom watering is especially great for tomatoes as fungal diseases can spread when they get their leaves wet. When you’re watering your mature tomato plants in the garden, try to water at the base and avoid splashing water on the leaves.
Before seedlings go out into the garden, make sure you give them some time to acclimatize to the outdoors. This is called “hardening off”. To start, choose an overcast, mild day (minimum 10°C) with little to no wind and put the seedlings outdoors for an hour or two. Over the next 7-10 days, gradually increase the time they’re left outside. Always pay attention to the weather when hardening off plants. Start with overcast days and build up to leaving them in the sun and light wind. Imagine if you’d grown up in a comfy controlled environment and suddenly you were put outside under a scorching sun or high winds. You wouldn’t like that at all! Never ever leave tomato seedlings out in very high winds as you’ll end up with a bunch of snapped stems and heartbreak. For some more details about hardening off check out this blog post.
TIP: if your tomato seedlings do get leggy don’t worry! This is a very common problem – especially when you don’t have lights and the tomatoes are stretching towards the window. Luckily there is a solution! Plant the tomato stem on its side! Some people actually always plant tomatoes this way. Dig a trench about 6 inches deep and lay the tomato seedling stem along it and then bury the stem with soil. Be very very careful not to snap the stem. Your planted tomato will likely be a bit crooked at first, but the roots that grow from the buried stem will help it to be a stronger, more vigorous plant as opposed to planting it with most of the stem out of the ground. Don’t simply dig a deep hole for the long seedling because that far down in the ground will be too cold for the plant’s roots.
Check out this video of planting tomatoes on their sides and their special tip for not breaking the stem.
*for more info check out Niki Jabbour’s in depth blog post about growing tomatoes from seed
Basil is an excellent companion to grow with tomatoes. They have similar requirements for light, soil, water and temperature. Not only do they taste great together but they may repel insects and some say they even enhance the taste of the tomatoes (as if home grown tomatoes could taste even better!?)
You can start basil seeds indoors at the same time as your tomatoes. Seed multiple seeds in 3-4 inch plug trays or pots and then directly transplant them into your garden with your tomatoes after the last frost date (around the first week of June for Halifax). If you’re planting into a container, you can plant the basil and tomatoes together if the container is big enough that the tomato won’t completely shade out the basil.
TIP: Once your basil seedling has grown several sets of true leaves (don’t count the cotyledons – the set that first appeared), you can pinch off the top two leaves. Be careful not to pinch too close to where the leaves connect because you could damage the new buds. Pinching like this will encourage those buds to grow into new stems and your basil plant will become much bushier as opposed to one tall and spindly stem.
Starting seeds indoors is a fun way to get your hands dirty growing plants while the weather can still be cold outside. These tips for tomatoes and basil transfer over to many other plants (except don’t plant seedlings deep like tomatoes unless directly specified!). The most important thing is to know when to start the seeds because they will differ with each vegetable. Growing vegetable from seed is an engaging and satisfying process – you get to watch them grow from the very time that the sprout pops through the potting mix to when you’re harvesting the first fruit or leaves to when you’re saving seeds to plant the next year. You also get to try varieties that you may not find as transplants – looking through seed catalogues is a fun winter pastime for garden lovers. So have fun, be creative, and enjoy! Happy gardening everyone!