Dra Elmarie,

I suggest you pay attention to the family of the weed plants. Asteraceae, for example, need pollination to produce viable seeds; the achene fruit-like seeds may be empty, and some species has very small fruit-like seeds;  Fabaceae, otherwise, can have hard seed coat. Thus, could you inform these parameters and I would like to help you. 

It is amusing that weeds grow fine in the wild, but when we want them to grow for research, they refuse to germinate.

Have you tried smoke/heat/fire? Could your soil type be less than optimal? (If you sterilized it, could you have killed off beneficial soil microbes as well?) Is there a daylength/ night;day ratio or some other timing that you haven't tried, or that might be delaying germination?

I'm not sure what your research interests are, but have you contacted any local herbicide researchers to try their techniques? Or some Botanic Gardens - there must be someone who germinates seeds on a regular basis.

Dear Elmarie Van der Watt

First check the viability of seeds by tetrazolium  staining. If the majority of seeds are viable, then break dormancy as follows:

- If the seed coat acts as a physical or mechanical barrier, scratch the seed coat.

- Keep the seeds in water for at least 2 hours to wash possible germination inhibitors.

- Treat the seeds with 10 mM GA3, which can overcome light and chilling requirements.

- Test the seeds for germination at optimum conditions in darkness.

Regards

Kazem Ghassemi-Golezani

You need to give information about the family of the species and deed characteristics. 

The seed size,testa  features, micropyle  size and location as well as the maturation stage at harvest. Are the seeds fresh or have been stored and for how long?

Are the seeds orthodox  or recalcitrant? These information are needed to help suggest pre-germination method that is appropriate. 

Need  more information on the species,  also check seed viability with TTC staining first 

Please provide more detail of family/ or genus level. It would be easier to suggest possible pre treatments

First check the seed germination under laboratory condition as per ISTA procedure analyse seeds..If the seeds are having hard seed coat please go for scarification treatment rubbing on sand paper or shaking with sand. if the seeds absorbed water but not germinated means go for seed treatment GA3 at 100 ppm or 2% KNO3 or 2% of Thiourea 

The first thing you need to do is add some more information to this question. When you say "weed" seeds are you talking about Cannabis? If not, you need to supply the species of plant. Also, you need to be sure you are working with seeds and not fruits. You may have to scarify the seeds in order to allow water into the sead. You can use a razor blade to nick the seed coat. You can also run them on sandpaper to make small breaks in the seed coat or. rub the seeds and some sandpaper and then soak the seeds so they can imbibe water.

I tried previously to overcome a rudimentary embryonic dormancy in barley seeds by incubating seed in cold temperatures. You stated that different methods did not lead to germination. In this case you have to suppose at least that the embryos are in viable !!

The question is without "question" too big.

Tell us all the names of the seeds. The purpose why you need to germinate them. 

Surely you cant germinate them all together in one bunch. As you see from all these good answers: each needs its own bit.

Thanks for the response guys I am asking for another student so will get more detail

First carry out tetrazolium (TZ) test and check the seeds are viable or not. If they take stain then try different treatments based on type dormancy persist in those seeds.

I with agree Dr. Bapurayagouda B Patil (TZ) test 1st.

What purpose do you have in germinate weeds seeds?

I with agree Dr. Bapurayagouda B Patil.

Si si escoges muestras de suelo y lo pones en condiciones normales en un invernadero, en tres dias a 30 dias habran germinado cientos de especies de ellas

Some weed seeds contain dormancy and require breaking this dormancy. In addition, they need special conditions for germination