Decoding seed sowing instructions
What is moist but not wet and why
When you have a potting mix with excellent drainage your mix will remain moist (damp for those who detest the word moist) but will not be sodden like a mud pie. Maintaining this balance ensures adequate moisture to cross the seed coat barrier or the testa. If the potting mix becomes too wet and does not drain well, oxygen can be displaced from the mix. Oxygen is essential for the aerobic respiration process of seed germination.
Also be aware of too dry which can lead to the death of your newly sprouted plants.
What is well drained
This leads us to what is a well drained mix (or a good quality mix), this is a complex question and I will dedicate a seperate post to this in due course. For this Q&A I have a simple answer.
Well drained means that when the media has finished dripping after watering, the remaining water retained by the media is enough for the biological processes of the seeds/plant and the spaces occupied by excess water are then filled by air which contains oxygen.
To recognise a well drained mix look for a potting mix that when you water it, it begins to drain just about straight away and only retains a small amount. When you are in doubt you can add perlite or coarse sand (3-4 mm in size) to the mix.
Below I have a photo of the coarse sand we use in our mixes, a well drained mix and a demonstration of a germination using a potting mix with too many fine particulars and a well drained potting mix using coarse sand.
Do not press down!, but everyone does. It’s what you do!
This is a bad idea. Do not press down ever. Plants, seeds, roots, fungi etc, they need to breath too. By pressing down you will displace the oxygen and reduce drainage in your mix. So you can see that good drainage and oxygen availability is super important. To ensure this seeds must never!!! ever be firmed down nor should the media be firmed after sowing. High oxygen levels in media are essential to prevent the growth of anaerobic disease organisms ie Phytophthora.
This goes for all planting. Potting up, in the ground, sowing seeds etc. Do not press down. Keep it airy and light.
Why does she keep saying to put a layer of gravel on top, doesn’t that usually go in the bottom of the pot.
Thankfully the myth of putting rocks, gravel, polystyrene in the bottom of a pot will help drainage is going away. This does nothing to help with drainage and in face makes it worse as there are less contact points for the water to drain. Roots need room, the pots are the size they are for a reason (nursery pots). Because to grow, roots need room to expand. You may notice I love good drainage, so to make sure you have this, do not put anything but potting mix in the pot.
Placing a fine layer of 2-3mm sized sand/gravel on top of the seeds sown helps with germination by allowing a certain amount of light and ensures a high oxygen environment. The gravel has the advantage of not being as easily displaced by water, this helps with keeping the seeds in position and not being washed out when watering the seedlings.
Why a sheltered position
Two reasons, one is quite logical, I have had a customer lose her seedlings because the cat knocked them down, in addition to this birds scratch them, rats eat them, the wind is a prick and blows them over. Secondly a sheltered position ensures that any rise or decline in media temperature will not occur rapidly. If it does it can damage seeds or prevent gemrnination.
Whaaaat, she is saying soak in hydrogen peroxide?? why!
This is an old trick, H2O2 imbibes the seed with water and provides it with a massive oxygen boost. When you are concerned the seed is old or not good quality this trick will vastly improve your germination chances. You only need a 1.5% solution which is 50:50 of the standard 3% solution available in supermarkets.
Seed treatment
I have noticed people like to play with seeds. Stratification, scarification etc. It is not as necessary as google would lead us to believe. Seeds that benefit from treatment I will have already treated. Baptisia seeds we do recommend you pour hot water over and leave for 24 hours before sowing, but for these exceptions I will note this on the seed packet. The best you can do is sow the seeds as soon as you get them. keep them in the sheltered spot and water regularly. For seeds that have specific environmental conditions, these will then be met naturally. The more playing around the higher the chances are of killing the seedlings.
Waiting for germination
Oh this is hard! I am the queen of poking with my finger and destroying the little plant babies. Don’t be me. Some plants take their sweet time and it is frustrating. We can get used to annuals that germinate within 14 days and then wonder why it hasn’t germinated. I like to think about the annual cycle of the plant. For example Erythroniums, they appear around late august, flower in September, produce seed late September, early October, die down end of October. If I sow my seed in October I am not going to get gemination until late August at least. 10 months of waiting.
All I can say is be patient. read about the plant you are growing, or ask me, and don’t do as I do, poke the seeds!
