Starting your seedlings too early or too late
Another common seed-starting mistake is starting them at the wrong time of year. If you start your seeds too early, they may get leggy, which just means they grow long and weak and flop over. They don’t have enough nutrients to support themselves when they’re young, so they grow tall in an attempt to reach the light source.
On the other hand, if you start your seeds too late in the season, there won’t be enough time for them to mature before it’s time to plant them outside or put them on display in their pots inside. The germination process can take anywhere from seven days to two weeks (and sometimes more), depending on how moist and warm your soil is.
To avoid either of these mistakes, figure out how many weeks it will take for your plants to reach maturity after germination and count back from that date. This will help you determine when it’s time for you to start planting.
Not using fresh seeds
To get seeds to grow, you need two things: water and warmth. But that’s not all. You also need fresh seed! Seeds have a shelf life, and their germination rates decrease over time. How long a particular seed will last depends on the type of vegetable it is, but in general the fresher the seed the better it will grow.
Here are some tips for keeping your seed fresh:
- Buy seed from reputable companies that sell high-quality products. If you’re reusing heirloom seeds from year to year or buying off of eBay, check to make sure they are fresh by conducting a germination test on them before planting them in your garden!
- Store leftover seeds in an airtight container in a cool dry place – preferably one with temperatures below 60 degrees and humidity less than 25%. A fridge or freezer is ideal; so is storing seeds in an envelope inside a mason jar with silica gel packets (commonly used to keep moisture out of shoeboxes).
Not starting seeds in the right pot
Once you’ve selected your seeds, it’s important to think about which kind of seed starting containers will best serve your plants. These containers come in many sizes: too large, and the soil will stay wet for days on end; too small, and the media could dry out quickly. You’ll want to choose a container that is small enough to fit easily on a windowsill or under grow lights and large enough so that you won’t have to transplant seedlings for at least 4 weeks.
Some options are more environmentally friendly than others; cardboard, paper pulp and newspaper pots can be composted directly into your garden along with the plant debris at season’s end while plastic pots—not so much (but they can be recycled). Some materials like peat pellets or seed starting trays disintegrate upon contact with water while other materials need good drainage holes in order to prevent the roots from becoming waterlogged and rotting. If you’re looking for something that can go straight into the ground after planting, select biodegradable options such as peat pellets or even small paper cups made by recycling toilet tissue rolls.
Thinning your seedlings too late, or not at all
Thinning is an important part of seed starting, but it’s also one of the hardest. After all, you’re essentially killing some of your plants. It’s important to thin your seedlings so that they have room to grow and get the sunlight, water and nutrients they need. If you don’t thin them, you’ll have a lot more dead plants than if you did.
When should you start thinning? As soon as the first leaves appear on your seedlings! This is called “true leaf” stage and means that their roots are developed enough to handle being moved elsewhere. It will be easier on them than waiting until their leaves are too big to move easily. You can wait a little longer, but once those leaves get real big (and real delicate), it will be harder on them when you pull them out by the roots.
Planting seeds too deep
Different plants require planting seeds at different depths. Check the packet, or run a quick Google search to find out the correct depth. If you plant seeds too deep, it can cause a number of problems.
Planting seeds too close together
As a general rule of thumb, seeds should be planted according to the spacing instructions provided on each seed packet. The distance between your plants will vary based on what you’re growing—some greens and herbs require little space and grow well in small containers, while larger crops like squash and tomatoes need plenty of room to spread out.
Packing too many seeds together in a pot or container is another common mistake among new gardeners. Planting them too close together will lead to mould growth, overcrowding, and competition for light and water, so it’s best to sow your seeds about 4-6 inches apart from one another (depending on what type of plant you are growing). Thinning out your seedlings later can be hard because you have to pull up part of the plant; however, if you do not thin out your seedlings then they will likely end up competing with one another for resources.
Getting too little light
Your plants need at least six hours of direct sunlight to produce a good crop. If you’re growing indoors, use a grow light to ensure your plant has the light it needs.
Plants that are not getting enough light are spindly and yellow.
Having the temperature too hot or cold
- If the temperature is too cold, you could get a space heater to sit near your seedlings.
- If the temperature is too hot, set up a fan to blow air over the seedlings.
A quick checklist
- Check when you should be planting
- Check the environmental requirements (light, temperature, soil)
- Is your seed package marked with a “fresh” date?
- Are your seeds still in the plastic bag?
- Did you wash them before planting?
- Did you plant what’s listed on the label for the range of your seeds?
- Did you have to wait long enough for your seedlings to grow inside their pots, or are they showing signs of stress already?