As part of the Master Gardener program we sometimes do little demonstrations or mini-workshops at the Oahu Urban Garden Center or farmers markets. A few months back I did some outreach at the Navy Exchange Garden Center and talked with folks about starting from seed. Many of the commercially available veggie plants do quite well in our climate, but the variety is lacking. You’re pretty much going to find the same nurseries supplying Home Depot, Lowes and all the other garden centers. Ordering seeds from places you like and trust is the alternative, but it’s an experiment! Not all varieties do well in our Hawaii climate- I have found certain types of tomatoes to be quite fussy and not worth the trouble, and “cool” weather kales can’t take the heat in certain parts of Oahu. I wrote about seeds vs. plants before, and it’s still a balance! It’s Fall here now, the days are a little bit shorter and cooler nights, which means I’m going to try again on some broccoli and some root veggies that didn’t do some well when we lived on the other side of the island.
The information below is from a handout I developed when doing Master Gardener outreach. I also blogged about my seedling setup here.
What sort of soil should I use?
Your growing medium needs to be a lightweight soilless mix. You can purchase prepared mixes or you can make your own. A good recipe is 9 parts sphagnum peat moss, 1 part perlite or vermiculite. This ensures a light mix and the perlite allows light to penetrate for those seeds that require light to germinate (not all do).
What should I put the seeds in?
You can sprout seeds in almost anything with drainage, but to ensure good root development the container needs to be a few inches deep. Re-use yogurt cups, nursery pots, or cut off the tops of soda bottles and insert holes. You do not have to purchase special containers. Clear containers are good when gardening with children to allow them to examine the roots developing.
Which seeds to start in pots, which ones to direct sow into the garden?
Generally, root vegetables, corn and beans do much better as a direct sow into the garden, but can be started in pots. Almost anything else can be started in pots then transplanted.
How much light do they need?
A window sill is not the best place to sprout seeds. In Hawaii, we do not necessarily need to worry about warming mats for germination (temperate climates usually do) but we do need to place our seeded pots under a light that is close to the soil surface, about 2 or 3 inches. This prevents new sprouts from “reaching” for the light and becoming “leggy” or having leaves on the top but a weak stem so they fall over. Any light will do, though you can purchase special growing lights. Some seeds germinate best in the dark, so you can cover your pots for 1 or 2 days first, and then allow them in the light. This mimics the dormant or winter process of being under snow or fallen leaves in nature.
How do I water them?
Moisture is important for germination, but you don’t want your pots too wet. A misting bottle is useful for keeping the soil moist and then water from the bottom if possible to encourage strong root development. You can do this if your seed pots are in another tray such as an under bed plastic storage box.
How many should I plant?
If sowing your seeds into individual pots, place at least 2 or 3 seeds in each. After they have germinated and you see leaves begin to form, you can cut the weakest ones to allow only the strongest plant to form roots.
When should I transplant?
Wait for “true leaves” to form before transplanting. You will know these because they look more true to the type of seed you have planted, such as rough edges on a tomato plant or leafy-looking on lettuce. Allow your new seedlings some time to acclimate to where you intend to put them outdoors before transplanting by setting them in their intended spot for 1 or 2 days first.
(HINT: When internet searching, search topic + extension to get Cooperative Extension research based documents. Example: “seed starting + extension”)
Get this handout as a document: