How to plant seeds in a flower pot

How to plant seeds in a flower pot

Planting seeds in pots

Planting seeds in pots

There are 3 main ways of sowing seeds:

  1. Sowing directly into the soil where they will grow.
  2. Sowing them into modules
  3. Sowing them into flowerpots. (or other containers) 

Here we are going to talk about sowing seeds in plant pots, flower pots or containers.

Here are some of the advantages of using pots:

 1. No weeds: You can be certain that the only seeds in the soil are the ones that you want to grow so there is no weeding or competition from weeds. 

2. Portability: Pots are portable and they can be moved around. For example moved into warmer or sunnier places or moved away from the cold if necessary. It is good for young seedlings  to have some air movement to strengthen the stems and also to have some direct sunlight. Plants tend to lean over to face where the light is coming from so you can move them around if light is coming from a narrow source.

3. Preparation: The purpose of growing seeds in pots is to raise small vigorous healthy plants.  When they are eventually planted into their final growing place as healthy robust plants all weeds can be destroyed at the moment of planting. If a mulch is applied immediately after planting our plants will have no competition and very little weeding will be necessary.

Which seeds are not suited to being sown in a flowerpot? 

I don’t plant very big seeds such as broad beans in pots. Some plants hate being transplanted so it is best to sow them where they will grow. Examples of these are root crops such as  carrots and parsnips. However if seedlings are handled very carefully they can be planted in pots. Radishes germinate very quickly and are very vigorous so it is best to plant them in the field. 

What type of soil should be used in the pot? 

The most important part of the soil in the pot is the first 3 cm. I fill up the flower pot with any old garden soil to within about 10cm from the top of the pot. Then I use some commercial potting compost soil from a  garden center to within 1.5cm from the top.  The soil right at the top should be fairly fine without any big lumps and it must be totally sterile. You can make your own seed compost for this purpose by putting some soil in a microwave or heating it up in a pan and then passing it through a sieve.  I tend to buy specialized seed compost from the garden center if they have any.

How to sow the seed? 

The most important factor is the depth that you put the seed. Very small seeds tend to  to be left on the surface and bigger seeds are planted deeper.   It often tells you on a seed packet the depth they should be planted. Some seeds need light to germinate whereas others will germinate in the dark.  Many people say that you should sow the seeds on the surface then cover them with other soil to the recommended depth. I tend to put the seeds on the surface and then mix them in with the end of a pencil so that most of them are more or less the correct depth. 

How long does germination take? 

Normally between 7 days and 3 weeks. The time is very dependent on temperature. Plants that need high temperatures to grow like pepper and aubergines like a high temperature say 20C. Cold tolerant plants such as cabbages will germinate at 8C.  The rate of germination depends on how old the seeds are.  In time the germination rate of a batch of seeds goes down until eventually they are all sterile. Below is a viability chart for common seeds.

  • 1 year: onions, parsnips, parsley, salsify, and spinach
  • 2 years: sweetcorn, peas, beans, chives, okra, dandelion
  • 3 years: carrots, leeks, asparagus, turnips
  • 4 years: peppers, chard, pumpkins, squash, watermelons, basil, artichokes
  • 5 years: most brassicas, beets, tomatoes, aubergine, cucumbers, celery, celeriac, lettuce, endive, chicory

What are common mistakes when planting seeds?
If you look at the pictures of novice gardeners on facebook, the biggest mistake is letting the seedlings go leggy.  Being leggy means having a very long thin stem. This is caused by having insufficient light and maybe being too warm.  A 10cm long seedling with a tiny thin stem and 2 small leaves at the top will most likely die very soon.  As soon as  seeds germinate they need lots of light and if they have been put in a high temperature to germinate they should be put in a cooler place. Seedlings grow stronger if they have some air movement which will make them sway around and strengthen the stems.  People growing plants inside in artificial lights use rotating fans.

The most common problem with seedlings is damping off. This is when the seedlings start to die and rot for no particular reason.  It is caused by  fungus or mould that thrives in cool, wet conditions.   If you have this problem, use sterilized pots or trays with good drainage and use clean new potting soil to prevent damping off. Pots can be sterilized with bleach and soil can be heated in a microwave  or a pot. To get complete sterilization,  you should heat the soil to between 80 and 90C for 30 minutes.  By the way, heated soil smells terrible. 

What to do with the seedlings? 
You have to wait until the seedlings are big enough to be transplanted. Generally speaking, seedlings should be more than 3 centimetres high. Seedlings can be either planted into small pots or modules or planted into the ground. 

Inverna Winter lettuce

Inverna Winter lettuce

The image above is of winter lettuce. It has actually been in the pot for some time. I have already potted up many seedlings from this pot into modules. These seedlings are big enough to be planted into the ground or into little pots. I would normally transplant the seedlings when they are smaller than they are in the photo.  In the background of the photo, you can see plastic modules. Seedlings can be planted into modules to let them get established.

Don’t forget to label your pots very clearly. You will need a permanent marker. Garden centres sell labels with a special pencil which will not become illegible.  In the past I have made home made  labels out of recycled  plastic bottles.  

How to transplant seedlings?
The only tools I use for this job is my index finger or if the seedlings are small I use a pencil. First I plunge my finger or a knife into the pot  to bring up a clump of seedlings. Then a seedling is pulled away from the clump. I only touch the seedling by the end of one of the leaves.  A hole is made in the place where the seedling is to be planted with a pencil or a finger and the root is lowered in. Afterwards, the soil is very gently  firmed down, then the seedling is watered in with some water from a cup or given a squirt from a spray. The seedling should not be lying down on the soil. The leaves should be in the air. They will take 2 or 3 days to get established. Some of them may die. In that case, just transplant another one from the mother pot.  This is a very pleasant activity on a sunny day. Make sure you listen to music while doing this activity. I find reggae is very suitable. 

Luke Jayne and Ditte transplanting seedlings

Other Comments
The soil that seeds are planted in does not  need any fertilizer. Once the seedlings have been transplanted, they benefit from some nutrients. They seem to like dilute shit tea. Just put some manure in a  bucket of water to soak for a while.  Dilute it with some water and pour over the plants. 

Maravilla Lettuce

Maravilla Lettuce

The image above shows the final product. These lettuce have been recently transplanted from modules. They will quickly expand and completely cover the soil. No weeds will be able to grow. 

Self-seeding Godetias

Godetias in a Pot

Godetias in a Pot

The other day I found a flower pot full of self seeded Godetia seedlings. I planted them about 6 years ago and they have survived in the pot on their own. The temperature in winter  gets well below 0C and in the summer it is very dry and well over 40C. The flowerpot has formed a tiny ecosystem and by an evolutionary process they have managed to survive.


Godetia Transplants

I have transplanted 18 of them into plastic modules and also planted the seeds which were in the dried seed pods into a pot.

I would like to make a self seeding area of Godetia plants which will come up every year. As they have survived for 6 years in very hostile conditions they should be able to cope with the harsh conditions at the Cortijo.

Notes: There are very precise instructions in Spanish for growing Godetia on this page
They germinate best at 21C, sowing in January will produce flowers in May/June.

I learned today that plastic modules in Spanish are called charolas

Godetias are actually called  Clarkias.



The Godetias looked very nice on the table for a long time.

The modules that I planted died after forgetting to water them during a weekend.
However the little seedlings that I planted in other pots were lovely. The Godetias flowered for about 4 weeks and were really lovely.

30 December – Seed Planting

Seed Pots

Seed Pots

This may seem a strange time to plant seeds. The reason why I can start seeds off now is because we have a place on the coast and one up in the mountains. The average temperature on the coast is about 14C and in the mountains it is 5C .The idea is to get the plants going and then transfer them to the mountains after March.

All the seeds here are plants that could cope with some low temperatures at the start.

I have planted several pots. If any of them germinate I will transplant them into pots or modules. Very tiny seeds are just sprinkled onto the surface. Bigger seeds are mixed into the soil with the ends of my fingers according to size. The soil is normal potting compost and at the top of the pots there is some finer seed compost which was bought at a garden centre.

Petunias (fire chief) wiki
Petunias are great flowers. They cope well with the hot sun and the don’t get too upset by an occasional lack of water and also they flower for ages.  Petunias normally only cost about 1.20 euros each for a potted one but it will be good if we can get loads of them to use in the summer. Petunia seeds are very small so they are just spread on the surface of the flowerpot.

Snapdragons - Antirrhinum

Snapdragons Antirrhinum wiki
These are the sort of hard as nails plants we like at the cortijo. There are some snap dragons alive and flowering  at the moment in the cortijo and the temperature has been down to -5C. A good quality about snaps is that they self-seed themselves and once there are a few growing they will establish a colony.



Tudela Lettuce (cogollos de Tudela in Spanish) wiki
Cogollos de Tudela are a really good Spanish lettuce that form very compact hearts. If you go to a Spanish restaurant you can order “cogollos” which is normally lettuce hearts drizzled with a sort of garlic oil. They are very healthy to eat and you can make a very quick almost 0 calorie snack by slicing  a cogollo lettuce heart into 4 laterally and drizzling on some extra virgin olive.

Capers (capparis Spinosa) (alcaparras in Spanish)  wiki
This is probably a waste of time because caper seeds are very difficult to germinate and require stratifying. They probably won’t germinate but you never know.

Parsnip (Pastinaca) (chirivía in Spanish)  wiki
These were some seeds that I has in an old packet. Let’s hope they germinate.

seed traysI have also planted lots of plants into seed trays. The trays cost about 2 euros. It is the best way of raising lots of small plants for later transplanting.

I normally buy my plants form a shop called Bolivar in Granada. (they cost about 8 cents each) This year I am going to try to grow some of them myself.

I have the following plants in the seed trays.
Cauliflowers  (coliflor in Spanish)  wiki
Cauliflowers do very well at the cortijo.

Spring onion  (cebolleta in Spanish)  wiki
The was a packet of White Lisbon which came free with Grow Your Own  magazine.

Kale (Black tuscany)  (col rizada in Spanish)  wiki
There were some seeds in the bottom of a packet. It is a type of Curly Kale with purple leaves.

Leek  (puero in Spanish)  wiki
I bought these seeds from Al Campo supermarket.

Brunswick Cabbage  (Col Repollo)  wiki


Propagating Geraniums

Every year I have to buy more Geraniums because at some point the temperature gets down to about -10C and kills them.

This year I have decided to propagate some geraniums by planting  cuttings at the house on the coast which has a mild climate.

I simply cut off the main stems from the parent plants and then protected the originals with garden fleece so that they might survive the winter.  I made cuttings about 15cm long, making the cut just below a node.  I left one healthy leaf on each cutting. I didn’t use any cutting hormones. (because I had forgotten to buy any). I used a plastic tray module.I did  this on the 28th December 2011. They were left in the open air. The climate is mild and rarely goes below 10C.

Blog post continued on 6th March 2013.

The picture below shows the overwintering geraniums from last year and new ones being propagated. Last year’s ones were a big success.
Propagating geraniums is easy.  The most important thing to do is spray them every 3 weeks to stop the stem boring caterpillars.