New Moon just passed and with much excitement we began this seasons seed sowing.
Each year we sow thousands of seeds to produce herbal babies for our own apothecary garden and for others through our herb nursery.
Over the years of teaching others how to grow medicinal plants we have come across the many common mistakes people make when sowing their herb seeds.
Although the specifics of each of the 250 species of medicinal plant we grow at Ivywood does vary BUT we have some top tips to share. Plus some specifics for sowing St. John’s Wort seeds with success. Here are some of our top factors to consider that will help you along your seed sowing journey.
Seed Viability
It is best to sow your seeds either straight away after saving from your Mammy plants OR within the next year. Correct storage of your saved or bought seed is crucial. After a year we find germination rates of most seeds decline dramatically.
Surface Sowing
Most medicinals are surface sown due to their size. This means they need light to germinate so we never cover them in seed compost. They need to be misted with a spray bottle TWICE a day to retain moisture for germination and are never left in direct sunlight. Read on to sowing St. John’s Wort seed for more specifics on this.
Heat
Until the seedlings emerge CONSISTANT heat is crucial. Most medicinals need 20 degrees Celsius for the entire germination phase. This phase differs for various plants. Some can take 5 days, whereas other can take 2 weeks. We recommend the home grower sowing in small trays or individual pots until they become familiar with how long each species takes to germinate. As we sow large amounts of seeds in trays with 96 modules we combine herbs in trays with similar germinate times.
Light
As soon as your seedlings appear they now need light (or even more light for those that are surface sown). They can now be moved onto watering with a small watering can or shower setting on a hose. Not keeping them in direct sunlight is still important!
A note on windowsill growing: A sunny windowsill in a house can get too much direct sunlight. It can be too hot during daylight hours and then too cold during nighttime hours. As consistence of heat is key we don’t recommend windowsill growing for medicinal herbs.
A Focus on St. John’s Wort (Hypericum perforatum) Seed Sowing
The best way to ensure your Hypericum seed sowing is a success is to have good seed! Saving your own seed from a friends plant or your own plants at the end of summer is ideal. Each year we create medicines from our Hypericum plants but always remember to select some plants to leave for seed saving.
When the next spring comes around we have our saved seed ready to sow to create hundreds of new Hypericum babies to pass onto others through our herb nursery.
The most common mistake people make with sowing Hypericum seed is that it needs light to germinate. Before sowing it is key to saturate the seed compost but not so much that the tray is dripping from the bottom. This can be done by using a rosette on a watering can or shower setting on your hose head. Do not compress the compost. Sow your seeds in its own tray with modules or pots. To sow your seed sprinkle 3-5 seeds in each module. Label your seeds!
Give the seeds a very light ‘misting’ with a spray bottle of water on mist or the mist setting on your hose head. It is vital to mist your seed tray twice a day. If you feel the compost has dried too much only ever water the tray from the bottom as any watering with a can from above could displace the seeds. Hypericum seeds need good light BUT not direct light in too hot a place. It can help to cover your seed tray on top with cling wrap until your seedlings appear. This can help retain moisture and avoid direct harsh sunlight.
As we begin our seeds sowing in early February we provide the trays with consistent heat on heated benches. But for your own seeds sowing of Hypericum from May onwards would not require a heated bench. Be aware that glasshouses and polytunnels have a huge temperature fluctuations between day and night in springtime. We cover seed trays each night with light fleece.
With consistent misting and limited temperature fluctuations your Hypericum seeds will appear in 1-2 weeks. Once up, they will come on fast given adequate light. They can now we watered from above using a watering can rosette or hose on shower setting. Only pot them on (which may include gentle splitting of seedlings if multiple seeds germinated in one tray module) once their roots are established. We would plant out our Hypericum plants in the end of April/ beginning of May. Make sure your plants are hardened off before planting out.
St. John’s Wort can take a year to fully establish itself in the garden for harvesting for making your own tinctures, essences, oils and drying for your tea mixes. Once settled it spreads to a manageable patch which can be left or split by root division to create more Hypericum beds!
If you would like to learn in person from us how to grow medicinal plants we run a Grow Your Own Medicinal Garden course here at Ivywood :)
