Growing seeds indoors is useful because it gives your plants a head start even if the weather outside isn’t warm, resulting in earlier and long harvests that would otherwise be possible. It’s particular good for tender crops such tomatoes, peppers and squash. It is particular good such a as tomatoes, peppers and squash. For best results, follow these top tips and make use of some gardening tools.
First use a good-starting soil. It needs to be fine and moisture-retentive so that the young seedlings don’t dry out. Seeds are usually planted at a depth of 1-2 times the size of their longest edge. And they need the soil above them to be gently firmed down. Then, water them with a fine-rosed watering can or spray. The soil needs to be fully moistened but not waterlogged so that they have air and don’t rot.
Plant seeds need warmth to germinate, so use a maximum-minimum thermometer to find somewhere in your house at the temperature indicated on the seed packet. However, warm soil does tend to dry out quickly, so to prevent this, you can either cover them with a plastic bag or regularly check and water them. The seed packet will usually tell you how many days it takes for them to germinate, but you need to check daily because as soon as they emerge, you will transfer them to somewhere with good strong natural light.
A common mistake is to place the seeds on a windowsill, which doesn’t often give the same strength of light as growing outdoors. This produces leggy seedlings and once they’ve started off badly, they will find it hard to recover. Most houses are already warm enough for seeds to grow, so if you are going to buy a propagator, it’s better to choose full=spectrum grow lights to supplement light, not heat, especially during late winter and early spring. There’s no point starting seeds too early, only to find they’ve outgrown their pots before the weather has warmed up enough outside. And starting seeds too late can mean they don’t have time to properly develop.
After a few weeks, the second seedlings will have developed their set of leaves, called their ‘true’ leaves because these are the ones that look like the final plant. At this stage, and before their roots get entangled, it’s good to transfer the best ones into their own pots. To do this, first prepare a new pot, making a suitable-sized hole. Then use something like a teaspoon to gently ease out the young plant’s roots. Always pick up the seedling by one of the leaves, not by the stem, because squeezing the stem at this early stage can damage the fine capillary tubes which carry water. Microscopic hairs on the roots are how the seedling draws up water and nutrients, so aim for the minimum of disturbance, taking as much soil as possible with the seedling. Then gently firm around it in the new pot to remove air pockets.
It may seem obvious, but many gardeners forget to label each pot and then have trouble identifying it when planting outside. Note down the variety you are growing, and dates such as when the seed was sown and transplanted so that you can learn which one perform best. Seedlings grown indoors are vulnerable to a lack of moisture, nutrients or warmth. Just like an intensive care unit, you need to make sure that you supply everything they need, so check on them at least once a day. Push your thumb into the soil or pick up the pot to feel how much water it contains. Check if they have enough light and warmth.
As the plants get larger, gradually introduce them to outside conditions—a process known as ‘hardening off’. Take them outside for just one hour a day at first, then increase this each day over a period of a week or more until they are finally ready to be planted. By following these tips, you’ll give your seedlings the very best chance of survival and set yourself up for a great harvest.