I am often asked about the sowing depths for seeds. The rule of thumb is no deeper that 2-3 times the distance across the widest part of the seed. That means very shallow for carrots so it’s best to sow onto the surface and cover with a very light amount of fine soil or bagged compost. If you soil is not fine enough then add compost and sow into it to ensure the seed has good contact with the growing medium. Water before you sow.
Revisiting some old research from a few years back I found these root depth and spread charts. Notice how deep the central or tap root can go with beetroot down to 10 feet and carrots to 8 feet. That is why it is best to make deep fertile soil by using lots of compost and mulch.
What a cold, dry and miserable April it has been. Too cold to sow or plant much outdoors as the soil temperature has been too low. If you are new to gardening or have an allotment for the first time don’t be pulled along by the old myths like planting certain crops on specific days of the year. The climate is changing and you must go with the best conditions to ensure success.
Have a look at this page which gives details of the minimum and optimum soil temperatures for some common veg. Remember this is the soil temperature at the depth the seed is planted and not the surface. If it remains dry, then seeds and transplants will need regular watering. Water in the day and not last thing at night as the ground and plants will stay cold all night.
Now the forecast is giving many hours of heavy rain for Monday 3 May, well it is a bank holiday!
Our garden slopes to one corner and the water goes with the flow. This can flood the sheds just out of shot. For some time I have been meaning to put in guttering to take the water off the paths and down a drain, the paving slabs have and intentional left to right slope. Today was the day when that little project was finished. Hope it works.
Today I sowed three types of onion seed; Sturon, Giant Stuttgart and Ailsa Craig in quarter width trays. They are on a heated base with the temperature set to 14C. This must mark the start of the new growing season although it is cold and damp outside with the forecast of snow.
Normally our onions are grown from sets but in 2020 we lost around 25% of the crop to white rot. As I am sure there have been no onions grown on the plot for many years I can only assume that it came with the sets. That explains the use of seed this year, to see if we can get clean onions that will store well.
We also had an attack of allium leaf miner so all alliums will be protected by insect proof netting this year.
Next to go in will garlic around Mid January if the weather is suitable. The cloves will be planted straight into the beds.
Radish seeds were sown between broad beans and peas on May 17th. Today there was good germination. It has been warm and they have been well watered so the conditions must have been exactly right. Instant gardening!
The seeds were sown on 1 May 2020. The first parsnips seeds germinated overnight, 12 days later. They were pre-soaked and sown on their edge. For details of the trial see this page.
The original setup had a tray of seeds pre-soaking on capillary matting. It proved impossible to keep it wet so was abandoned and replaced by a tray of Tagetes minuta (Mexican marigold) seeds which germinated in 3-4 days.
Tagetes minuta – Marilgolds
The trial has been stopped. It showed that getting the temperature right and consistent does indeed help germination. The way seeds were planted either on edge of flat made little difference to the germination rates. The key is to ensure that the seed is in good contact with the compost. That means a fine tilth especially for small seeds.
Seeds sown direct in beds on 10 April have started to germinate – carrots, parsnips, broad beans and peas in modules. Still no sign of the leeks sown in modules but there is time enough to resow if needed.
I must admit to having never lost the fascination of seeing seeds germinate.
Now is the time to plan follow on crops for winter. Just found this book which we got several years back. This year we want to get it right so that there is food right through until next spring.
At this time of year, the ground can still be too cold to sow seeds direct. The answer is to sow under cover or in a greenhouse if you have one. You can even use a windowsill in the house that does not get long periods of strong sunlight or the seeds may overheat. Facing east or west is best. But even that might not be warm enough for things like tomatoes and courgettes. The answer is to use either a small heated propagator or a heat mat under seed trays.
Seeds vary and need different temperatures for optimum germination. A partial list of temperature can be found here
The photo shows trays of tomatoes, courgettes and strawberry seeds shown on 22 March. They will each germinate at different times and will need pricking out into small pots in a few weeks.
This is a “Trio Top Electric Windowsill Propagator” from Kings Seeds. There are other makes. It is also worth checking out our local Derbyshire suppler Two Wests & Elliot The usual disclaimer, I have no connection with either company other than as a customer.
Look out for updates as the seeds germinate and information about what to do next.
Seeds grow with very little help from us. These are lettuce, Tom Thumb and Little Gem. We plant smaller varieties because they can picked and eaten in one go. No limp lettuce from the fridge when you grow your own.
Top left are Tom Thumb, bottom right Little Gem
There is nothing special needed, you can use margarine containers with holes in the bottom as seed trays. Use fresh, bagged peat free compost as soil from the garden is too heavy and dense. Water sparingly, don’t over water.