Q: This year, I want to grow annual and biennial bedding plants from seeds. I plan to start the seedlings indoors before moving them outside when it's warmer. What soil should I use?
A: 'For sowing seeds of annual and biennial bedding plants, the ideal compost is one specifically formulated for seeds and cuttings,' says a gardening expert. 'Such composts have a finer texture compared to standard potting mixes, preventing seeds from getting lost and ensuring proper moisture retention.'
Additionally, unlike other compost types – including homemade compost – these blends are lower in nutrients, which aren't needed until seedlings are a few weeks old.
Many brands of seed and cuttings compost are available, so it's wise to check your local garden center or DIY shop. For online shoppers, highly-rated options include Miracle-Gro Seed Starting Mix and Burpee's Organic Seed Starting Mix, both sold on Amazon.
The Royal Horticultural Society (RHS) recommends using fresh compost yearly for seedlings, as old compost can be mixed with new for plants that are more established.
This expert has been writing about gardening for over 50 years and frequently answers readers' inquiries. He has published four books and gives numerous talks on horticulture.
Select a soil that is fine and not overly rich
Does soil choice affect seed starting success?
While it may seem extravagant to use specialized compost for initial sowing before transferring to multipurpose compost, this practice is highly beneficial for nurturing strong, productive plants in your flower beds and containers.
'Once seedlings can be handled, you can shift them to pots with nutrient-rich compost for their ongoing growth,' notes the expert. 'Opt for multi-purpose, peat-free composts that are light for easy watering, yet with slightly elevated nutrient levels to foster rapid growth in seedlings.'
A specialized mix will give your plants a strong start
What soil is best for vegetable seed sowing?
This horticulturally trained expert previously worked as a professional kitchen gardener, cultivating edibles for restaurants and a cookery school.
Some vegetables should be sown directly into the ground rather than in trays, according to this specialist. 'Root crops like carrots and parsnips prefer direct sowing, as they do not respond well to root disturbance.' Transplanting these can lead to damaged roots or distorted growth.
Conversely, tender crops like tomatoes and aubergines thrive when started indoors before being potted for greenhouse growth or hardened off for outdoor planting. Starting seeds indoors can also help achieve an earlier harvest.
For these indoor sowings, using a sterilized seed compost is recommended, just like with annual and biennial plants.
